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Spaying female and castrating male dogs, hereinafter referred to as neutering, is a US convention for the first year in the dogs life. Research on 35 breeds of dogs revealed that early neutering increases risks of joint disorders, such as hip dysplasia (HD), elbow dysplasia (ED), or cranial cruciate ligament (CCL) tear, or cancers, such as lymphosarcoma (LSA), mast cell tumor (MCT), hemangiosarcoma (has), or osteosarcoma (OSA), for some breeds. Joint disorder risks are heightened for some larger breeds and for mixed-breed dogs weighing more than 20 kg. Some breeds had elevated risks for cancers. Several other research teams have reported health complications associated with neutering. The study goal includes using the same methodology for data collection and analyses as in the study on 35 breeds for five additional dog breeds weighing at least 20 kg. The breeds were: German Short/Wirehaired Pointer, Mastiff, Newfoundland, Rhodesian Ridgeback, and Siberian Husky. Major differences among breeds appeared in vulnerability to joint disorders and cancers with early neutering: male and female Pointer breeds had elevated joint disorders and increased cancers; male Mastiff breeds had increased CCL and LSA and females had non-significant elevated CCL risks; female Newfoundland breeds had heightened risks for joint disorders and males had non-significant elevated risks; female Ridgeback breeds had heightened MCT with very early neutering; and Siberian Huskies showed no significant effects on joint disorders or cancers, but female breeds showed a non-significant but elevated CCL. Updated guidelines cover 40 dog breeds. These results further emphasize the importance of personalized decisions regarding the neutering of dogs, considering the dogs breed, sex, and context.

Background: Canine mast cell tumors (MCT) in the skin are classified into cutaneous (cMCT) and subcutaneous (scMCT) types, which exhibit different clinical behaviors. Although these types have been classified only by histology, preoperative differentiation is important for proper surgical planning. Aim: To examine the accuracy of differentiating these types based on the gross features before surgery. Methods: Gross photographic and histologic features of 52 MCTs (2014–2022) were retrospectively compared between cMCTs and scMCTs. Based on these results, we grossly classified additional 25 MCTs (2007-2013) into two forms using photographic observations. These observations were then compared with the results of histological classification performed by a blinded pathologist. Results: The most notable difference between the two forms was hair loss on the tumor surface. Hair loss was prominent in all 36 cMCTs but minimal or absent in all 16 scMCTs. Histologically, only the cMCT showed prominent follicular reduction due to MCT infiltration. Using the hair loss feature, we classified an additional 25 MCTs: 15 cMCTs, 7 scMCTs, and 3 unclassifiable cases with overlapping features. Agreement with histological classification was 80% (12/15) for cMCT and 100% (7/7) for scMCT. Among the unclassifiable cases, one was cMCT and two were scMCT. Large tumors (3.5-10.5 cm) were found in two of the three unclassifiable cases and in all three cases without agreement. Conclusion: Hair loss on the tumor surface is a distinct feature of cMCT that enables accurate visual differentiation from scMCT, except for some large MCTs. This may assist in surgical planning, specifically for sc-MCT. [Open Vet J 2024; 14(11.000): 2774-2779]

Abstract Background Information regarding response rate to tigilanol tiglate for mast cell tumors in dogs is limited. Objectives Report the response rate and durability of tigilanol tiglate intratumoral treatment in dogs with mast cell tumors presented to veterinary oncologists. Animals One hundred forty‐nine dogs; 151 individual tumors. Methods Multicenter, retrospective survey‐based study. Veterinary oncologists subscribed to the American College of Veterinary Internal Medicine (ACVIM) oncology listserv were solicited for information from dogs treated with tigilanol tiglate. An electronic survey was used to collect information at initial treatment, 1 month and 1 year after treatment. Results Most tumors were cutaneous, occurred on the limbs and were cytologically low grade. Seventy‐five percent of dogs achieved a complete response after 1 dose of tigilanol tiglate 1 month after treatment. This response was durable at 1 year in 64% of dogs for which data were available (n = 88). Wound formation, an expectation after treatment, occurred after a median of 7 days (range, 1‐91 days), with a median wound area of 4.71 cm2 (range, 0.09‐100 cm2). Wounds took a median of 30 days to heal completely (range, 14‐154 days). A moderate association between tumor volume and wound size was confirmed. Conclusions and Clinical Importance Tigilanol tiglate is an effective local treatment option for mast cell tumors in dogs with a predictable clinical course and response. Because of the unique mode of action and clinical course, client education and careful case selection is necessary before electing tigilanol tiglate for local treatment.

OBJECTIVE To determine the myelosuppressive effects/hematological toxicities, other general toxicities, and when these occur during vinblastine/prednisolone chemotherapy in dogs bearing high-grade or metastatic cutaneous/subcutaneous mast cell tumors (MCTs). METHODS Medical records were retrospectively reviewed between November 1, 2016, and March 1, 2023. Thirty client-owned dogs with histopathologically confirmed cutaneous high-grade MCTs/metastatic subcutaneous MCTs and that subsequently completed a 12-week vinblastine/prednisolone chemotherapy protocol were included. Hematology was assessed before commencing chemotherapy and before each vinblastine treatment. The effect of each treatment upon hematological values was evaluated. Measured outcomes included the type, frequency, and severity of hematological and other more general toxicities. RESULTS 24 of 30 dogs experienced at least 1 hematological toxicity, 6 experienced gastrointestinal toxicity, and 4 experienced lethargy. The most common toxicity was anemia (15/30 [50%]), with 93.3% (14/15 dogs) classified as Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events grade I and 6.6% (1/15) classified as grade 11. The second most common toxicity was neutropenia (14/30 [46.696]), with 71.4% (10/14) classified as grade I and 28.6% (4/14) as grade 111. The least common hematological toxicity was thrombocytopenia (4/30 [13%]), all grade I. Neutropenia mainly occurred during weeks 2 and 3; however, there was no significant decrease in neutrophil count relative to baseline. Neutrophil count increased and Hct decreased during weeks 6 to 12 of treatment when compared to baseline. No change in platelet count was observed. CLINICAL RELEVANCE Vinblastine/prednisolone chemotherapy leads to hematological toxicity; however, this was mostly low-grade and did not require major intervention. Vinblastine/prednisolone chemotherapy is well tolerated in dogs bearing highgrade Or metastatic MCTs. [ABSTRACT FROM AUTHOR]

Cutaneous and subcutaneous mast cell tumors (MCTs) are common canine neoplasms characterized by variable biological behavior. Tumor-associated macrophages (TAMs) and tumor-infiltrating lymphocytes (TILs) can be effective prognostic markers in numerous human neoplasms and are increasingly investigated in dogs. The aim of this study was to characterize immune cells in canine MCTs and their relationship with histological location (cutaneous, subcutaneous) and histologic nodal metastatic status (HN0-3). Thirty-eight MCTs (26 cutaneous, 12 subcutaneous) from 33 dogs with known sentinel lymph node (SLN) metastatic status were immunolabeled for Iba1 (macrophages), CD20 (B cells), CD3 (T cells), and Foxp3 (regulatory T cells). Semiquantitative scoring of interstitial and perivascular CD3+, CD20+, and Foxp3+ cells and morphological evaluation of Iba1+ cells were performed. For each marker, the percent immunopositive area was evaluated by image analysis. All MCTs were diffusely infiltrated by Iba1+ cells and variably infiltrated by CD20+, CD3+, and rare Foxp3+ cells. Stellate/spindle Iba1+ cells were associated with HN2 and HN3 SLNs. Perivascular Foxp3+ cells, CD3+ cells, and percent CD3+ areas were increased in subcutaneous MCTs. Interstitial CD3+ cells were increased in cutaneous MCTs with HN0 SLNs. No differences in CD20+ cells were identified between cutaneous and subcutaneous MCTs and among SLN classes. MCTs were markedly infiltrated by TAMs and variably infiltrated by TILs. Stellate/spindle morphology of TAMs associated with HN2 and HN3 SLNs is suggestive of a pro-tumoral (M2) phenotype. Cutaneous and subcutaneous MCTs have different tumor-immune microenvironments, and T-cell infiltration might contribute to prevention of nodal metastatic spread of cutaneous MCTs. [ABSTRACT FROM AUTHOR]

Background: Information regarding response rate to tigilanol tiglate for mast cell tumors in dogs is limited. Objectives: Report the response rate and durability of tigilanol tiglate intratumoral treatment in dogs with mast cell tumors presented to veterinary oncologists. Animals: One hundred forty‐nine dogs; 151 individual tumors. Methods: Multicenter, retrospective survey‐based study. Veterinary oncologists subscribed to the American College of Veterinary Internal Medicine (ACVIM) oncology listserv were solicited for information from dogs treated with tigilanol tiglate. An electronic survey was used to collect information at initial treatment, 1 month and 1 year after treatment. Results: Most tumors were cutaneous, occurred on the limbs and were cytologically low grade. Seventy‐five percent of dogs achieved a complete response after 1 dose of tigilanol tiglate 1 month after treatment. This response was durable at 1 year in 64% of dogs for which data were available (n = 88). Wound formation, an expectation after treatment, occurred after a median of 7 days (range, 1‐91 days), with a median wound area of 4.71 cm2 (range, 0.09‐100 cm2). Wounds took a median of 30 days to heal completely (range, 14‐154 days). A moderate association between tumor volume and wound size was confirmed. Conclusions and Clinical Importance: Tigilanol tiglate is an effective local treatment option for mast cell tumors in dogs with a predictable clinical course and response. Because of the unique mode of action and clinical course, client education and careful case selection is necessary before electing tigilanol tiglate for local treatment. [ABSTRACT FROM AUTHOR]

Introduction: Mast cell tumors (MCTs) have been described as a form of cancer affecting a specific type of blood cell that typically plays a role in the body's reaction to allergens and inflammatory processes. The MCTs have been classified as skin tumors in dogs which can also affect other areas of the body, such as the spleen, liver, gastrointestinal tract, and bone marrow. The present study investigated the clinical and histological signs, biological behavior, and treatment of primary oral mast cell tumors. Case report: A 3-year-old neutered female, weighing 18 kg and classified as a medium mixed breed, was referred to a veterinary clinic in Mashhad (Iran) due to the presence of a pink, lobulated mucosal mass located on the internal surface of her lower lip. Although the vital signs were normal, clinical examination, radiology, and an incisional biopsy were performed from the lesion site under general anesthesia for histology study. Histopathological features were similar to those of mastocytoma in this case. On presentation, no concurrent mass was found on other sides of the body. Mandibular lymph nodes were not enlarged; however, the incisor teeth of the mandible were loosed. Accordingly, the primary oral MCTs were diagnosed. The surgery was done and After a follow-up period of 150 days post-excisional surgery for a Mast cell tumor, the patient remained alive and exhibited no visible signs of tumor recurrence or surgical complications. Conclusion: The current case report defined a primary Mast cell tumor with slow tumor growth and without metastasis in the mucosal surface of the lower lip in a dog treated by complete excisional surgery only, unlike some previous studies of primary oral MCTs in dogs with aggressive biological behaviors. [ABSTRACT FROM AUTHOR]

Background: Gynura procumbens, a well-known traditional herb, has been studied to be an effective chemotherapeutic agent against a wide range of cancer cell types. Case Description: A 7-year-old chihuahua dog was presented to the VTH with multiple cutaneous MCT grade III masses found on the cranial aspect of the right front leg and the dorsal aspect of the neck/back. Local excision of all cutaneous tumors were performed followed by chemotherapy (vinblastine, prednisone and cyclophosphamide) every 21-day interval for 9 treatments. Nearby three months later, recurrent MCT was observed and lomustine was used instead for 21-day interval. During the first chemotherapy, the dog had a fever, weak, lethargy and vomiting. Alternative natural therapy preferred, the dog has been received Gynura procumbens daily. The dog responded well to this herbal treatment. These recurrent masses began to shrink after a few weeks of treatment. Several months of treatment, all masses were completely gone. Moreover, no micro-metastasis to lungs, spleen and liver were detected. Conclusion: This natural herbal was helpful to stop the growth of tumor, to prevent micro-metastasis and to relieve the patient's symptoms. [Open Vet J 2024; 14(6.000): 1491-1496]

Spaying female and castrating male dogs, hereinafter referred to as neutering, is a US convention for the first year in the dog's life. Research on 35 breeds of dogs revealed that early neutering increases risks of joint disorders, such as hip dysplasia (HD), elbow dysplasia (ED), or cranial cruciate ligament (CCL) tear, or cancers, such as lymphosarcoma (LSA), mast cell tumor (MCT), hemangiosarcoma (has), or osteosarcoma (OSA), for some breeds. Joint disorder risks are heightened for some larger breeds and for mixed-breed dogs weighing more than 20 kg. Some breeds had elevated risks for cancers. Several other research teams have reported health complications associated with neutering. The study goal includes using the same methodology for data collection and analyses as in the study on 35 breeds for five additional dog breeds weighing at least 20 kg. The breeds were: German Short/Wirehaired Pointer, Mastiff, Newfoundland, Rhodesian Ridgeback, and Siberian Husky. Major differences among breeds appeared in vulnerability to joint disorders and cancers with early neutering: male and female Pointer breeds had elevated joint disorders and increased cancers; male Mastiff breeds had increased CCL and LSA and females had non-significant elevated CCL risks; female Newfoundland breeds had heightened risks for joint disorders and males had non-significant elevated risks; female Ridgeback breeds had heightened MCT with very early neutering; and Siberian Huskies showed no significant effects on joint disorders or cancers, but female breeds showed a non-significant but elevated CCL. Updated guidelines cover 40 dog breeds. These results further emphasize the importance of personalized decisions regarding the neutering of dogs, considering the dog's breed, sex, and context. [ABSTRACT FROM AUTHOR]

Objective: The objective of the study was to describe clinical and histologic characteristics of eyelid (LMCT) and conjunctival (CMCT) mast cell tumors in dogs and cats presented to a referral clinic in Germany. Animal Studied: Medical records were reviewed to identify dogs and cats diagnosed with LMCTs or CMCTs between 2006 and 2020. Results: LMCT were diagnosed in 31 patients and were cutaneous (n = 28; 20 dogs and 8 cats) or subcutaneous (three dogs). Five cases involved the mucocutaneous junction (four dogs, one cat). CMCTs occurred only in dogs (n = 3). At the time of presentation two of the four canine LMCT cases involving the mucocutaneous junction had metastasized to a mandibular lymph node. When applying the Kiupel system, both these cases were categorized as high grade. 85.7% (18/21) of the canine (19 cutaneous and 2 subcutaneous) LMCT and all CMCT cases were categorized as Kiupel low grade. No local recurrences occurred in all LMCT cases in which clean surgical margins were obtained (n = 18, mean surgical margin width: dogs 9.4 mm, cats 3.8 mm). Two cats (2/4) and four dogs (4/7) with questionable or incomplete surgical margins experienced local recurrences (mean time to recurrence of 180 and 637 days in dogs and cats, respectively). Conclusion: Recurrence of low‐grade LMCTs and CMCTs following excision with clean margins is rare. Tumors involving the mucocutaneous junction may be of higher grade and prone to lymphatic metastasis. [ABSTRACT FROM AUTHOR]

Disease monitoring of amphibian assurance populations is an important buffer against ongoing global extinctions. This study documents a high incidence of neoplasia in a zoo-managed assurance population of Puerto Rican crested toads (Peltophryne lemur ; PRCTs). Over 5 years, neoplasia was diagnosed in 17/49 (35%) submitted adult PRCTs and was the cause of death or euthanasia in 13/17 (72%). Most toads were male (16/17; 94%) and 6 to 11-years-old (average 8.1 years). Notably, seven toads (41%) had multiple neoplasms. Of the 29 neoplasms identified, 17 (59%) were cutaneous or subcutaneous. The most common neoplasms included mast cell tumors (MCTs; 8/29; 28%), histiocytic sarcomas (6/29; 21%), lymphoma/leukemia (4/29; 14%), and squamous cell carcinomas (3/29; 10%). Distant metastases were documented in 6/8 (75%) toads with MCTs. Causes for neoplasia in this population were not determined though may include genetic or environmental factors. Continued investigations of managed endangered amphibians will help elucidate mechanisms of carcinogenesis. [ABSTRACT FROM AUTHOR]

Mast cell tumors (MCTs) are the most common skin tumors in dogs. Clinical data and cytological examination typically suffice for the initial diagnosis. However, prognosis and appropriate treatments necessitate histopathological examination. Amid global concerns regarding hazardous chemicals, the utilization of natural dyes has garnered increased attention. In this context, we focused on using butterfly pea flower (BPF) extract, rich in anthocyanins, as a dye for canine histopathological MCT staining. The dried petal powder was dissolved in distilled water (DW), filtered to obtain a crude extract, and then subjected to a freeze-drying process to preserve its quality. The BPF-dye was prepared by adding DW and 2.5% NaCl into the dried extract. The paraffin serial sections of 32 diagnosed MCTs were stained with the dye for 2 hours. Additionally, the sections were stained with Hematoxylin and Eosin, and Toluidine blue (TB) routine dyes for MCT diagnosis. Sections of non-MCT round cell tumors were also stained with BPF-dye. The results revealed pink-reddish specific staining in the neoplastic mast cell granules, with different staining levels corresponding to the degree of cytoplasmic granulation, similar to TB staining. However, TB staining exhibited blue or metachromasia, indicating differences in staining color. Additionally, the BPF-dye could differentiate MCT from non-MCT round-cell tumors, providing an alternative method of differentiation. The dye maintained its staining ability for 60 days when stored at 4oC. Accordingly, it holds potential as an alternative dye for MCT diagnosis, being locally available and eco-friendly. Further study should focus on improving the stability and longevity of the dye by preserving its anthocyanin content with natural co-pigments for practical application. [ABSTRACT FROM AUTHOR]

Spaying female and castrating male dogs, hereinafter referred to as neutering, is a US convention for the first year in the dog's life. Research on 35 breeds of dogs revealed that early neutering increases risks of joint disorders, such as hip dysplasia (HD), elbow dysplasia (ED), or cranial cruciate ligament (CCL) tear, or cancers, such as lymphosarcoma (LSA), mast cell tumor (MCT), hemangiosarcoma (has), or osteosarcoma (OSA), for some breeds. Joint disorder risks are heightened for some larger breeds and for mixed-breed dogs weighing more than 20 kg. Some breeds had elevated risks for cancers. Several other research teams have reported health complications associated with neutering. The study goal includes using the same methodology for data collection and analyses as in the study on 35 breeds for five additional dog breeds weighing at least 20 kg. The breeds were: German Short/Wirehaired Pointer, Mastiff, Newfoundland, Rhodesian Ridgeback, and Siberian Husky. Major differences among breeds appeared in vulnerability to joint disorders and cancers with early neutering: male and female Pointer breeds had elevated joint disorders and increased cancers; male Mastiff breeds had increased CCL and LSA and females had non-significant elevated CCL risks; female Newfoundland breeds had heightened risks for joint disorders and males had non-significant elevated risks; female Ridgeback breeds had heightened MCT with very early neutering; and Siberian Huskies showed no significant effects on joint disorders or cancers, but female breeds showed a non-significant but elevated CCL. Updated guidelines cover 40 dog breeds. These results further emphasize the importance of personalized decisions regarding the neutering of dogs, considering the dog's breed, sex, and context.

Introduction: The presence of cancer in dogs was detected by Raman spectroscopy of urine samples and chemometric analysis of spectroscopic data. The procedure created a multimolecular spectral fingerprint with hundreds of features related directly to the chemical composition of the urine specimen. These were then used to detect the broad presence of cancer in dog urine as well as the specific presence of lymphoma, urothelial carcinoma, osteosarcoma, and mast cell tumor. Methods: Urine samples were collected via voiding, cystocentesis, or catheterization from 89 dogs with no history or evidence of neoplastic disease, 100 dogs diagnosed with cancer, and 16 dogs diagnosed with non-neoplastic urinary tract or renal disease. Raman spectra were obtained of the unprocessed bulk liquid urine samples and were analyzed by ISREA, principal component analysis (PCA), and discriminant analysis of principal components (DAPC) were applied using the Rametrix®Toolbox software. Results and discussion: The procedure identified a spectral fingerprint for cancer in canine urine, resulting in a urine screening test with 92.7% overall accuracy for a cancer vs. cancer-free designation. The urine screen performed with 94.0% sensitivity, 90.5% specificity, 94.5% positive predictive value (PPV), 89.6% negative predictive value (NPV), 9.9 positive likelihood ratio (LR+), and 0.067 negative likelihood ratio (LR-). Raman bands responsible for discerning cancer were extracted from the analysis and biomolecular associations were obtained. The urine screen was more effective in distinguishing urothelial carcinoma from the other cancers mentioned above. Detection and classification of cancer in dogs using a simple, non-invasive, rapid urine screen (as compared to liquid biopsies using peripheral blood samples) is a critical advancement in case management and treatment, especially in breeds predisposed to specific types of cancer. [ABSTRACT FROM AUTHOR]

Simple Summary: The aim of this study was to evaluate a new microscopic parameter (atypical mitotic figures) in canine cutaneous mast cell tumors regarding the ability to predict patient survival (prognosis). Mast cell tumors are one of the most common skin tumors in dogs. Counting the number of tumor cells undergoing division (mitotic figures) is of prognostic importance for this tumor type. While normal cells have a highly regulated cell division (normal mitotic figures), tumor cells might exhibit errors during chromosome separation into daughter cells. These errors can be identified microscopically as atypical mitotic figures and are described as a malignancy criterion for some human tumors. In this study, we have shown that a high number of atypical mitotic figures in canine cutaneous mast cell tumors is predictive of shorter patient survival. As compared to enumerating all mitotic figures, increased numbers of atypical mitotic figures (≥3 per 2.37 mm2) had a higher specificity for tumor-related death. These findings should be validated in future studies. Cell division through mitosis (microscopically visible as mitotic figures, MFs) is a highly regulated process. However, neoplastic cells may exhibit errors in chromosome segregation (microscopically visible as atypical mitotic figures, AMFs) resulting in aberrant chromosome structures. AMFs have been shown to be of prognostic relevance for some neoplasms in humans but not in animals. In this study, the prognostic relevance of AMFs was evaluated for canine cutaneous mast cell tumors (ccMCT). Histological examination was conducted by one pathologist in whole slide images of 96 cases of ccMCT with a known survival time. Tumor-related death occurred in 11/18 high-grade and 2/78 low-grade cases (2011 two-tier system). The area under the curve (AUC) was 0.859 for the AMF count and 0.880 for the AMF to MF ratio with regard to tumor-related mortality. In comparison, the AUC for the mitotic count was 0.885. Based on our data, a prognostically meaningful threshold of ≥3 per 2.37 mm2 for the AMF count (sensitivity: 76.9%, specificity: 98.8%) and >7.5% for the AMF:MF ratio (sensitivity: 76.9%, specificity: 100%) is suggested. While the mitotic count of ≥ 6 resulted in six false positive cases, these could be eliminated when combined with the AMF to MF ratio. In conclusion, the results of this study suggests that AMF enumeration is a prognostically valuable test, particularly due to its high specificity with regard to tumor-related mortality. Additional validation and reproducibility studies are needed to further evaluate AMFs as a prognostic criterion for ccMCT and other tumor types. [ABSTRACT FROM AUTHOR]

Increased or constitutive activation of nuclear factor kappa B (NF-kB) is a feature of many chronic disease processes, including cancer. While NF-kB overactivation has been documented extensively in human oncology, there is a relative paucity of data documenting the same phenomenon in veterinary medicine. To assess NF-kB activity, antibodies to p65 and p100/p52, which are components of NF-kB heterodimers, were first validated for specificity and canine cross-reactivity via Western blot and labeling of immortalized cell pellets. Then, nuclear labeling for these antibodies was assessed via QuPath software in over 200 tumor tissue samples (10 hemangiosarcomas, 94 histiocytic sarcomas, 71 lymphomas, and 28 mast cell tumors) and compared to immunolabeling in appropriate normal tissue counterparts. Greater than 70% of spontaneous canine tumors evaluated in this study had more nuclear p65 and p100/p52 immunoreactivity than was observed in comparable normal cell populations. Specifically, 144/204 (70.58%) of tumors evaluated had positive p65 nuclear labeling and 179/195 (91.79%) had positive p100/p52 nuclear labeling. Surprisingly, greater nuclear p100/p52 reactivity was associated with a longer progression-free survival (PFS) and overall survival (OS) in canine lymphomas. These results provide support and preliminary data to investigate the role of NF-kB signaling in different types of canine cancer. [ABSTRACT FROM AUTHOR]

Lymph node mapping has become a prominent method in veterinary oncology in recent years, given the superior specificity of sentinel lymph node (SLN), assessment over regional lymph node (RLN), evaluation in determining the cancer stage. Human medicine has long benefited from various mapping techniques, and recently, these approaches have gained traction in veterinary medicine as well. Methods applied for lymph node mapping in veterinary oncology encompass indirect lymphography (IL), computed tomography lymphography (CTL), colorimetric mapping, contrast-enhanced ultrasound (CEUS), lymphoscintigraphy, and near-infrared fluorescence (NIRF). This article offers an overview of each method, discussing their accessibility and features. Additionally, the study provides insights into indirect lymphography, endorsing it as reliable, cost-effective, and widely accessible technique. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To determine the prevalence of splenic malignancy in cats undergoing splenectomy and to investigate possible factors associated with post-operative outcome. ANIMALS: 62 client-owned cats that underwent splenectomy. METHODS: Medical records of 4 UK-based referral hospitals were searched and data reviewed retrospectively over 17 years. Factors associated with outcomes post-splenectomy were analyzed. RESULTS: 50 out of 62 cats (81%) were diagnosed with splenic neoplasia. Mast cell tumor ([MCT], 42%), hemangiosarcoma ([HSA], 40%), lymphoma and histiocytic sarcoma (6% each) were the most common tumor types. Fifteen cats (24%) presented with spontaneous hemoabdomen and were all diagnosed with splenic neoplasia. The diagnostic accuracy of cytology to detect splenic malignant lesions was 73% (100% for MCTs and 54% for mesenchymal tumors). Median survival time for cats with nonneoplastic splenic lesions was 715 days (IQR, 18 to 1,368) and 136 days for cats with splenic neoplasia (IQR, 35 to 348); median survival time was longer for cats with splenic MCT when compared to cats with HSA (348 vs 94 days; P < .001). Presence of metastatic disease and anemia (PCV < 24%) at diagnosis were associated with a poorer survival when considering all cats. Presence of anemia, a splenic mass on imaging or spontaneous hemoabdomen were associated with a diagnosis of HSA (P < .001). CLINICAL RELEVANCE: Benign splenic lesions were uncommon in this cohort of cats. Spontaneous hemoabdomen should prompt the clinician to suspect neoplasia in cats with splenic disease. Anemia and evidence of metastasis at diagnosis were poor prognostic factors regardless of the final diagnosis. [ABSTRACT FROM AUTHOR]

Cutaneous mastocytosis (CM) is a rare condition in young dogs characterized by multicentric cutaneous proliferation of neoplastic mast cells. Clinical data from 8 dogs that met inclusion criteria (age of onset less than 1.5 years, greater than 3 lesions) were obtained via a standardized survey. Biopsy samples were classified by the Kiupel/Patnaik grading systems and analyzed for c-KIT mutations. The median age of onset was 6 months (range: 2–17 months). Dogs had 5 to more than 50 lesions characterized as nodules, plaques, and papules. Seven dogs were pruritic. Clinical staging in 2 dogs did not reveal visceral involvement. No dogs had systemic illnesses at diagnosis. Histologically, CM was similar to cutaneous mast cell tumor (cMCT). Two dogs had neoplasms classified as high-grade/grade II while 6 dogs had low-grade/grade II neoplasms. No dogs had mutations in c-KIT exons 8 and 11. Treatment included antihistamines (8/8), corticosteroids (7/8), lokivetmab (3/8), and toceranib (1/8). Six dogs were alive with lesions at the end of the study with a median follow-up time of 898 days, while 2 dogs were euthanized. In dogs with high-grade/grade II neoplasms, one continued to develop lesions at 1922 days post-diagnosis, while the other dog was euthanized at 56 days post-diagnosis. One dog was euthanized 621 days post-diagnosis due to rupture of a neoplasm. CM occurs in young dogs and is histologically indistinguishable from cMCT. Current histologic grading systems did not apply uniformly to the dogs of the study and further studies are needed. [ABSTRACT FROM AUTHOR]

Simple Summary: Oncology is a rapidly advancing field in small-animal medicine, underscoring the importance of innovative therapeutic approaches. Tyrosine kinase inhibitors (TKIs) are drugs that block various important cellular functions and play an important role in treating cancer in people and dogs. However, their role in feline oncology is less established. This comprehensive review surveys the existing literature on tyrosine kinases (TKs) and the use of TKIs in cats, aiming to identify knowledge gaps, speculate on potential indications and lay the groundwork for future investigations. Diverse feline tissues have been examined for various TK expressions. However, although limited evidence exists on the use of TKIs in specific feline tumors, it trails behind progress in human and canine oncology. We believe additional research could identify new uses for these drugs and improve therapeutic options for cats with cancer in the future. Tyrosine kinase inhibitors (TKIs) have become invaluable in the treatment of human and canine malignancies, but their role in feline oncology is less defined. While toceranib phosphate and masitinib mesylate are licensed for use in dogs, no TKI is yet approved for cats. This review systematically maps the research conducted on the expression of tyrosine kinases in neoplastic and non-neoplastic domestic feline tissues, as well as the in vitro/in vivo use of TKIs in domestic cats. We identify and discuss knowledge gaps and speculate on the further research and potential indications for TKI use in cats. A comprehensive search of three electronic databases and relevant paper reference lists identified 139 studies meeting the inclusion criteria. The most commonly identified tumors were mast cell tumors (MCTs), mammary and squamous cell carcinomas and injection-site sarcomas. Based on the current literature, toceranib phosphate appears to be the most efficacious TKI in cats, especially against MCTs. Exploring the clinical use of TKIs in mammary carcinomas holds promise. Despite the progress, currently, the evidence falls short, underscoring the need for further research to discover new indications in feline oncology and to bridge the knowledge gaps between human and feline medicine. [ABSTRACT FROM AUTHOR]

Simple Summary: Cytological evaluation of lymph nodes (LN) during staging of canine Mast Cell Tumors (MCTs) is a hot topic. While histology is currently the gold standard of LN evaluation, cytology would have the advantage of in vivo investigation that allows for the planning of a therapeutical approach. However, at present, LN cytological examination and interpretation needs to be standardized. In the present work, the significance of the nodal mast cell number in dogs with and without MCT has been investigated, comparing different counting methods and different sample preparation techniques. Our results suggest that, while counting methods and sample preparation technique do not influence MC count, the nodal MC number can discriminate between metastatic and non-metastatic LNs, but fails to distinguish between metastatic and possibly metastatic LNs. Cytological evaluation of lymph nodes (LN) in canine cutaneous mast cell tumors (MCT) has a key role in MCT staging. However, cytological discrimination between metastatic and reactive LNs is debated and diagnostic criteria inconsistent. The aim of this study was to retrospectively quantify nodal mast cells (MCs) in non-oncological (NOD) and MCT-bearing dogs (MCTBD), using different sample preparation techniques, to evaluate the significance of the MCT number. Cytological specimens from NOD-LNs (10 fine-needle aspirates—FNAs) and MCTBD-LNs (10 FNAs, 10 scrapings, 10 touch imprints) were evaluated. MCTBD-LNs were grouped in: non-metastatic, possibly-metastatic, and metastatic based on current literature criteria. MCs were counted in 4, 8, and 20 high-power-fields, and over 500, 1000, and 2000 total cells. MCs were significantly more numerous in MCTBD-LNs than in NOD-LNs and in "metastatic" samples than in "non-metastatic". There was no significant difference between "metastatic" and "possibly metastatic" samples. Sample preparation techniques did not influence these results. A negative correlation between MCs number and sample cellularity was observed. Results were confirmed regardless of the counting method applied. MCs counting per se cannot distinguish possibly metastatic and metastatic cytological samples. Sample preparation technique and the counting method applied seem to have no influence on cytological quantification of nodal MCs in MCTBDs. [ABSTRACT FROM AUTHOR]

Neutering (including spaying) of male and female dogs in the first year after birth has become routine in the U.S. and much of Europe, but recent research reveals that for some dog breeds, neutering may be associated with increased risks of debilitating joint disorders and some cancers, complicating pet owners' decisions on neutering. The joint disorders include hip dysplasia, cranial cruciate ligament tear or rupture, and elbow dysplasia. The cancers include lymphoma, mast cell tumor, hemangiosarcoma, and osteosarcoma. In previous studies on the Golden Retriever, Labrador Retriever and German Shepherd Dog, neutering before a year of age was associated with increased risks of one or more joint disorders, 2-4 times that of intact dogs. The increase was particularly seen with dogs neutered by 6 months of age. In female Golden Retrievers, there was an increase in one or more of the cancers followed to about 2-4 times that of intact females with neutering at any age. The goal of the present study was to expand and use the same data collection and analyses to cover an additional 29 breeds, plus three varieties of Poodles. There were major breed differences in vulnerability to neutering, both with regard to joint disorders and cancers. In most cases, the caregiver can choose the age of neutering without increasing the risks of these joint disorders or cancers. Small-dog breeds seemed to have no increased risks of joint disorders associated with neutering, and in only two small breeds (Boston Terrier and Shih Tzu) was there a significant increase in cancers. To assist pet owners and veterinarians in deciding on the age of neutering a specific dog, guidelines that avoid increasing the risks of a dog acquiring these joint disorders or cancers are laid out for neutering ages on a breed-by-breed and sex basis.

Simple Summary: This study aimed to characterize the molecular profiles of immune checkpoints RANK/RANK-L and IFN-γ in high-grade mast cell tumors and lymph node metastases to understand the complex activities occurring in the tumor microenvironment. All tumors showed moderate or intense immunolabeling of PD-L1, CTLA-4, RANK, RANK-L, and IFN-γ, and the lymph node metastases presented moderate or intense immunolabeling of checkpoint proteins. In conclusion, the high-grade MCTs were characterized as immunosuppressive microenvironments, showing an increase in the RANK/RANK-L signaling pathway and intensified immune checkpoint immunoreactivity, which may explain an intratumoral escape mechanism and indicating high sensitivity to immunotherapy. Therefore, PD-L1, RANK/RANK-L and IFN-γ may be useful in the clinical management of dogs with high-grade MCT. Mast cell tumors (MCTs) are the most common malignant cutaneous tumors in dogs, and they present extremely variable biological behavior. The interaction between RANK, RANK-L, and immune checkpoints is frequently detected in the tumor microenvironment, and, together, they participate in every stage of cancer development. Thus, the aim of this study was to characterize the molecular profiles of PD-L1, CTLA-4, RANK/RANK-L signaling pathway, and IFN-γ in primary tumors and lymph node metastases. Formalin-fixed, paraffin-embedded slides of MCTs and metastatic lymph nodes of ten dogs were submitted to immunohistochemical investigations. The results demonstrated that the tumor microenvironment of the high-grade mast cell tumors showed moderate or intense immunolabeling of all proteins, and the lymph node metastases also showed moderate or intense immunolabeling of checkpoint proteins. In addition, MCTs larger than 3 cm were associated with intensified PD-L1 (p = 0.03) in metastatic lymph nodes and RANK-L (p = 0.049) immunoreactivity in the tumor. Furthermore, dogs with a survival time of less than 6 months showed higher PD-L1 immunoreactivity (p = 0.042). In conclusion, high-grade MCT is associated with an immunosuppressive microenvironment that exhibits elevated RANK/RANK-L signaling and enhanced immune checkpoint immunoreactivity, potentially facilitating intratumorally immune escape. These biomarkers show promise as clinical indicators of disease progression and might response to immunotherapy in dogs with high-grade MCTs, thus emphasizing their importance for guiding treatment decisions and improving outcomes. [ABSTRACT FROM AUTHOR]

A 5-year-old Labrador Retriever presented with a subcutaneous mass on the right scapular region with localized calor. On magnetic resonance imaging (MRI), a heterogeneously hypointense mass was seen on T1-weighted images (WI) and hyperintense on T2WI and fat-suppressed T2WI with marginal contrast enhancement on postcontrast T1WI and invasion into the surrounding tissue. Histopathological examination of the mass confirmed subcutaneous mast cell tumor (MCT) infiltrating to the adjacent subcutaneous fat. This is the first report to describe the MRI findings of subcutaneous MCT in veterinary medicine. This study suggests that MRI may help evaluate the extent of invasion of subcutaneous MCT. [ABSTRACT FROM AUTHOR]

Simple Summary: The increasing relevance given to sentinel lymph node assessment in veterinary medicine has led to the necessity of evaluating different mapping techniques and their combination. This study was performed in dogs with mast cell tumors after preoperative assessment identification of draining nodes using lymphoscintigraphy. The aim was to assess whether the addition of methylene blue dye to intraoperative detection of radioactivity in lymph nodes increased the surgical identification of such nodes. Dogs included totaled 103, for a total of 116 mast cell tumors and 196 biopsied lymph nodes. Adding the removal of blue-stained lymph nodes to radioactive positive nodes, the detection of metastatic lymph nodes increased from 90% to 95%. A low percentage of nodes detected in the single lymphocenter were both unstained and non-radioactive. Interestingly, all lymph nodes considered overtly metastatic at histopathology were radioactive. Only a few self-limiting side effects were recorded. The results of this study reported an advantage of the combination of intraoperative gamma probe and methylene blue for guiding the dissection of sentinel lymph nodes in dogs with mast cell tumors. Methylene Blue (MB) is combined with radiopharmaceutical for intraoperative sentinel lymph node (SLN) mapping, but its role during SLN extirpation has not been investigated yet in veterinary medicine. The aim of this study was to assess whether MB increased surgical detection of SLN beyond the use of intraoperative gamma-probe (IGP) alone in clinically node-negative dogs with mast cell tumors (MCTs) following the detection of sentinel lymphocentrums (SLCs) via preoperative planar lymphoscintigraphy. Dogs enrolled underwent MCT excision and SLC exploration guided by both MB and IGP. Data recorded for each SLN were staining (blue/non-blue), radioactivity (hot/non-hot), and histopathological status (HN0-1 vs. HN2-3). A total of 103 dogs bearing 80 cutaneous, 35 subcutaneous, and 1 mucocutaneous MCTs were included; 140 SLCs were explored, for a total of 196 SLNs removed. Associating MB with IGP raised the SLNs detection rate from 90% to 95%. A total of 44% of SLNs were metastatic: 86% were blue/hot, 7% were only blue, 5% were only hot, and 2% were non-blue/non-hot. All HN3 SLNs were hot. Combining MB with IGP can increase the rate of SLN detection in dogs with MCTs; nonetheless, all lymph nodes identified during dissection should be removed, as they might be unstained but metastatic. [ABSTRACT FROM AUTHOR]

The current gold standard treatment for canine mast cell tumors (MCT) uses vinblastine sulfate (VBL) as chemotherapy, although tyrosine kinase inhibitors (TKI) have recently been shown to be worthy candidates for treatment. This systematic review aimed to analyze the overall survival (OS), progression-free survival (PFS), overall response rate (ORR), and complete (CR) or partial response (PR) in dogs with MCT treated with TKI compared to standard VBL treatment. The systematic review was registered in the Open Science Framework (OSF) database under the identifier 10.17605/OSF.IO/WYPN4 (https://osf.io/). An electronic search was performed in nine databases. References from eligible studies were also selected to find more registers. A total of 28 studies met the eligibility criteria, and one more was recovered from the references of eligible studies, totaling 29 selected studies. The overall response rate, complete response, and partial response were higher in dogs treated with tyrosine kinase inhibitors than in dogs treated with vinblastine. The overall survival and progression-free survival of vinblastine-treated dogs were higher compared to tyrosine kinase inhibitors-treated dogs. Dogs with mutated KIT treated with tyrosine kinase inhibitors have longer overall survival and progression-free survival compared to those treated with vinblastine. It is important to consider the limitation of the study which should temper the interpretation of the results, videlicet, the extracted data lacked sample standardization and included variables such as animal characteristics, mutation detection methods, tumor characteristics, and treatment types which may have influenced the outcome of the study.Systematic review registrationhttps://osf.io/, identifier: 10.17605/OSF.IO/WYPN4.

An approximately 12‐year‐old female Vietnamese Pot‐Bellied Pig was presented to the Mississippi State College of Veterinary Medicine Food Animal Service for anorexia of 2 days duration. On physical examination, the patient appeared depressed and lethargic with significantly pale mucus membranes, open mouth breathing, and nostril flaring. On abdominal palpation, the abdomen was tense and uncomfortable. A complete blood count (CBC) and chemistry profile were performed. The CBC revealed significant anemia and mild leukocytosis characterized by mild neutrophilia with a left shift. Mast cells were rarely observed. Hematocrit = 8.1% (RI 22‐50), RBC = 1.25 × 106/μL (RI 3.6‐7.8), WBC = 19.85 × 103/μL (RI 5.2‐17.9), Neutrophils = 15.08 × 103/μL (RI 0‐11.4), and Bands = 0.993 × 103/μL (RI 0‐0.019). The chemistry profile was unremarkable with a mildly elevated BUN and slightly decreased total protein and albumin (BUN = 39 mg/dL [RI 4.2‐15.1], total protein = 6.2 g/dL [RI 6.6‐8.9], and albumin = 2.5 g/dL [RI 3.6‐5.0]). An abdominal ultrasound revealed numerous hypoechoic nodules diffusely scattered throughout the hepatic parenchyma. An FNA of one of the hepatic nodules was performed. A mild suppurative component and numerous variably granulated mast cells were observed. A presumptive cytologic diagnosis of mast cell tumor was made. Histopathology was performed, confirming the cytologic interpretation. [ABSTRACT FROM AUTHOR]

Simple Summary: Mast cell tumor (MCT) is the most common malignant skin tumor in dogs. In order to gain more information on the prognostic markers of MCT, the role of the eosinophil granulocytes infiltrates was investigated and assessed by the evaluation of tumor-associated tissue eosinophilia (TATE) in 87 canine cutaneous MCTs. In human medicine, high TATE are often described in highly angiogenic tumors: we therefore assessed the vascular endothelial growth factor (VEGF) expression in neoplastic mast cells. TATE and VEGF expression were compared between themselves, with other variables expressing the biological behavior of the tumor, and with the recurrence. High grades of TATE resulted to be associated with less differentiated tumors, with higher recurrence rates, and with aberrant expression of KIT. This is the first evaluation of the association between TATE and the biologic behavior of MCTs. This study suggests that TATE investigation could be an important source of information for this tumor and for other neoplasms. Mast cell tumor (MCT) is the most common malignant skin tumor in dogs. In order to gain more information on the prognostic markers in MCT, the role of the eosinophil granulocytes infiltrates was investigated and assessed by the evaluation of tumor-associated tissue eosinophilia (TATE) in 87 canine cutaneous MCTs. In human medicine, high TATE are often described in highly angiogenic tumors: we therefore assessed the vascular endothelial growth factor (VEGF) expression in neoplastic mast cells. TATE and VEGF expression were compared between themselves, with histological grading, immunohistochemical expression of KIT and Ki-67, and with the recurrence. We found a statistically significant correlation between TATE and Patnaik grading (p = 0.041), Kiupel grading (p = 0.022), immunohistochemical KIT expression (p = 0.015), and tumor recurrence (p = 0.000). No associations were observed with Ki-67 and VEGF expression. This is the first evaluation of TATE and its prognostic value in canine MCTs in veterinary oncology. This study suggest that this investigation could be an important source of information for this tumor and for other neoplasms. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are a class of noncoding RNA molecules playing a crucial role in tumor modulation targeting mRNA. This study aimed to validate the diagnostic potential of a panel of 3 miRNAs previously identified in canine mast cell tumors (MCTs), miR-21, miR-379, and miR-885, as markers of lymph node involvement in terms of histological absence (nonmetastatic: HN0; premetastatic: HN1) and presence (early-metastatic: HN2; overt-metastatic: HN3) of metastasis, in the saliva of mast cell tumor (MCT)-affected dogs by quantitative polymerase chain reaction (PCR). Forty-seven saliva samples were analyzed: 36 from MCT-affected dogs (12 subcutaneous [3 HN0-1 and 9 HN2-3] and 24 cutaneous [9 HN0-1 and 15 HN2-3—MCT]) and 11 from healthy dogs. MCT-group effects were investigated using analysis of variance (ANOVA). The origin of the tumor affected the expression of salivary miR-21 (P =.011) with an increase in cases with subcutaneous MCTs compared with the healthy group (P =.0005) and those with cutaneous MCTs (P =.004). Salivary miR-21 was higher in the HN2-3 class compared with the healthy group (P =.004). Salivary miR-885 was not affected by the presence of MCT, while miR-379 was not detected in saliva. The diagnostic potential of salivary miR-21 in discriminating MCT-affected dogs from the healthy group (AUC = 0.8917), cutaneous from subcutaneous (AUC = 0.8111), and subcutaneous HN0-1 (AUC = 0.7250) and HN2-3 (AUC = 0.9750) classes from healthy samples was demonstrated by receiver operating characteristic curve analysis. Overall, salivary miR-21 was identified as a promising tool, representing a novel approach to detecting MCT-associated epigenetic alterations in a minimally invasive manner. [ABSTRACT FROM AUTHOR]

The diagnosis of canine mast cell tumor (MCT) via cytology carries the risk of triggering life-threatening anaphylactic reactions due to massive histamine release. Since mast cells release various lipid mediators, which are excreted in urine, we aimed to explore urinary lipid metabolites as potential non-invasive diagnostic markers for MCT. Liquid chromatography-mass spectrometry-based analysis detected 32 types of lipid metabolites in the urine of MCT dogs. Among these, urinary levels of 15-deoxy-δ-12,14-PGJ 2 , lyso-PAF, 9,10-DiHOME, and 12,13-DiHOME were significantly elevated in MCT dogs compared to healthy dogs. These urinary lipid metabolites could serve as novel non-invasive biomarkers for canine MCT.

Small extracellular vesicles (sEV) are a class of extracellular vesicles (30–150 nm), delivering molecules including proteins, metabolites, and microRNAs (miRNAs), involved in physiological intercellular crosstalk and disease pathogenesis. The present pilot study aims are (I) to develop an easy and fast protocol for the isolation of sEV from plasma of mast cell tumor (MCT)-affected dogs; (II) to evaluate if miR-21-5p (sEV-miR-21-5p), a miRNA overexpressed by MCT, is associated with sEV. Seventeen dogs have been enrolled in the study: 4 healthy and 13 (6 with and 7 without nodal metastasis) MCT-affected dogs. sEV were isolated using size exclusion chromatography (SEC) (IZON column 35nm) and were characterized by Western blot, Nanoparticle tracking analysis, and transmission electron microscopy. sEV-miR-21-5p was quantified using digital PCR. sEV expressed the specific markers CD9 and TSG101, and a marker of mast cell tryptase. The sEV mean concentration and size were 2.68E + 10 particles/ml, and 99.6 nm, 2.89E + 10 particles/ml and 101.7 nm, and 3.21E + 10 particles/ml and 124 nm in non-metastatic, nodal metastatic, and healthy samples, respectively. The comparative analysis demonstrated that the level of sEV-miR-21-5p was significantly higher in dogs with nodal metastasis compared to healthy (P = 0.038) and without nodal metastasis samples (P = 0.007). In conclusion, the present work demonstrated that a pure population of sEV can be isolated from the plasma of MCT-affected dogs using the SEC approach and that the level of sEV-miR-21-5p is higher in nodal metastatic MCT-affected dogs compared with healthy and MCT-affected dogs without nodal involvement.

Cell division through mitosis (microscopically visible as mitotic figures, MFs) is a highly regulated process. However, neoplastic cells may exhibit errors in chromosome segregation (microscopically visible as atypical mitotic figures, AMFs) resulting in aberrant chromosome structures. AMFs have been shown to be of prognostic relevance for some neoplasms in humans but not in animals. In this study, the prognostic relevance of AMFs was evaluated for canine cutaneous mast cell tumors (ccMCT). Histological examination was conducted by one pathologist in whole slide images of 96 cases of ccMCT with a known survival time. Tumor-related death occurred in 11/18 high-grade and 2/78 low-grade cases (2011 two-tier system). The area under the curve (AUC) was 0.859 for the AMF count and 0.880 for the AMF to MF ratio with regard to tumor-related mortality. In comparison, the AUC for the mitotic count was 0.885. Based on our data, a prognostically meaningful threshold of ≥3 per 2.37 mm2 for the AMF count (sensitivity: 76.9%, specificity: 98.8%) and >7.5% for the AMF:MF ratio (sensitivity: 76.9%, specificity: 100%) is suggested. While the mitotic count of ≥ 6 resulted in six false positive cases, these could be eliminated when combined with the AMF to MF ratio. In conclusion, the results of this study suggests that AMF enumeration is a prognostically valuable test, particularly due to its high specificity with regard to tumor-related mortality. Additional validation and reproducibility studies are needed to further evaluate AMFs as a prognostic criterion for ccMCT and other tumor types.

Cutaneous mast cell tumor (MCT) is one of the most frequent cutaneous neoplasms of dogs and may vary from well-differentiated to aggressive tumors with metastasis. The authors retrospectively described the gross and histologic aspects of metastatic MCT in 49 dogs. Primary MCT was most commonly identified in the inguinal region (14/35; 40%), and at necropsy multiple, cutaneous nodules were frequently reported (23/49; 47%). All primary MCT were classified as high-grade neoplasms, and metastases involved the lymph nodes (47/49; 96%), spleen (33/49; 67%), liver (29/49; 59%), bone marrow (20/49; 41%), kidneys (16/49; 33%), and heart (14/49; 29%), while the lungs were less commonly affected (9/49; 18%). The main gross findings included lymphadenomegaly in 47 cases; splenomegaly in 28 cases, with splenic nodules in 13 dogs; hepatomegaly in 28 cases, with white pinpoint foci in 9 cases; nodules on the capsular surface of the kidneys in 9 dogs; and epicardial nodules in 6 cases. Histologically, the lymph nodes were largely obliterated by neoplastic mast cells, while in the spleen, neoplastic cells were multifocally scattered (16/33; 48%), arranged in nodules (10/33; 30%), or obliterated the parenchyma (9/33; 27%). In the liver, the neoplastic cells mainly infiltrated the sinusoids (24/29; 83%), but were also arranged in random nodules (10/29; 34%). Interstitial and nodular metastases were observed in the kidneys and the heart. Grossly unapparent metastases were common in the heart (6/14; 43%), kidneys (4/16; 25%), and lungs (6/9). KIT III and KIT II staining patterns were observed in 29 and 20 cases, respectively. [ABSTRACT FROM AUTHOR]

Mast cell tumors (MCTs) are an uncommon primary neoplasm of the nasal cavity in dogs for which there is a paucity of existing literature regarding their clinical behavior and molecular features. The objectives of this retrospective study were to examine the clinical findings, histopathologic and immunohistochemical features, and c-KIT mutation status of primary intranasal MCTs in dogs and identify potential prognostic factors. Canine biopsies submitted to a diagnostic laboratory in Colorado between 2010 and 2019 with intranasal neoplasms diagnosed as MCTs and no history of cutaneous or oral MCT were considered. Immunohistochemistry for CD117 and Ki67 and polymerase chain reaction (PCR) for internal tandem duplications at exons 8 and 11 of the c-KIT gene were performed. Twenty out of 1849 (1%) primary intranasal neoplasms were MCTs. Metastases were reported in 11/20 cases (55%), with the mandibular lymph node representing the most common site. One case had distant metastases to abdominal viscera. Of the cases with available outcome data, 6/14 (43%) died or were euthanized from MCT-related disease within 1 year of the onset of clinical signs. Only one case had a c-KIT mutation at exon 11. In our study, intranasal MCTs were prone to metastasize and had a generally poor prognosis, resembling the behavior of MCTs arising in other mucosal locations. While dogs with metastatic disease and survival times of <1 year tended to have atypical KIT localization, moderate to high Ki67 indices, and mitotic counts ≥8, definitive prognosticators could not be identified due to the limited number of cases with favorable clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: Skin tumors are the most frequently diagnosed lesions, of which 7-21% are mast cell tumors (MCTs). There is a great effort to identify factors that can influence the prospective course of MCTs. Though, the histological grade is considering an important predictor helping to determine the malignancy and metastatic potential of MCTs. Aim: In this study, an epidemiological analysis of risk factors (breed, age, sex, and anatomical site) for dogs having MCTs was evaluated considering the respective MCTs histological grade in comparison to other skin tumors. Methods: The study included 244 dogs affected by cutaneous MCTs from a universe of 1,185 dogs diagnosed with skin tumors. A univariable analysis with Fisher exact test was performed to determine the odds ratios (ORs) with 95% confidence intervals. Results: Boxers had a higher predisposition to Patnaik’s grade I (OR=5.9, 95% CI 2.648-13.152) and to Kiupel’s low-grade MCTs (OR=2.6, 95% CI 1.539 - 4.447). Labrador retrievers (OR=2.1, 95% CI 1.423-3.184) and pugs (OR=12.9, 95% CI 2.336-70.931) had a predisposition for Patnaik’s grade II MCTs and Kiupel’s low-grade lesions (OR=2.3, 95% CI 1.478 - 3.597; OR=17.1, 95% CI 3.093 - 94.377, respectively). French bulldogs had a higher risk to grade III MCTs (OR=7.9, 95% CI 2.381 - 26.072). Pit bulls had a predisposition to grade III MCTs and Kiupel’s high-grade tumors (OR=4.4, 95% CI 1.221 - 16.1 and OR=4.962, 95% CI 1.362 - 18.077, respectively). Bull terriers (OR=12.7, 95% CI 2.098 - 76.818) presented higher risk for having low-grade MCTs. The perigenital area and trunk exhibit a greater risk for high grading lesion (OR=6.6, 95% CI 2.679 - 16.334; OR=1.9, 95% CI 1.028 - 3.395, respectively) and the limbs had a predisposition to grade II tumor (OR=1.6, 95% CI 1.134 - 2.395). A decreased risk of having MCT was seen in older dogs (from 7-10 years and 11-18 years) compared to that in the reference group (4-6 years). Conclusion: When comparing to canine skin tumors, this study showed a relationship between MCT histological grading and the risk factors, age, breed and topography of canine MCTs. The variations noted in the clinical presentation of MCTs amongst predisposed dog breeds reinforces the relevance of the genetic background in MCTs carcinogenesis.

Background and Aim: CD 117 (c-KIT) internal tandem duplication (ITD), octamer-binding transcription factor 4 (Oct-4), and sex-determining region Y-box 2 (Sox-2) may govern the oncogenicity and aggressiveness of canine cutaneous mast cell tumor (MCT) in the crossbred dogs. Thus, a comprehension of this matter may help us establishing a novel platform to treat the disease in those dogs. However, evidence has lacked so far. Thus, this study aimed to survey CD 117 ITD, Oct-4, and Sox-2 expressions and their relations to the 2-tier grading in a group of Thai crossbreed dogs. The study was done using polymerase chain reaction (PCR), Reverse transcription PCR (RT-PCR), and immunohistochemistry. Materials and Methods: Thirty-three MCT specimens graded by the 2-tier histopathology grading were collected from the crossbred and purebred dogs. CD 117 ITD was detected by conventional PCR and immunohistochemistry. While, Oct-4 and Sox-2 expression levels were determined at the protein and mRNA levels by immunohistochemistry and RT-PCR, respectively. The expression magnitude of each parameter was then related to the grades and breeds. Results: About 60.61% of specimens were low grade, while 39.39% were high grade. CD 117 ITD was not detected in all specimens. A significant increase of Oct-4 expression was found in the high-grade, crossbred dogs. Meanwhile, Sox-2 expressions were increased both in the purebred and crossbred dogs with high-grade MCT. Conclusion: The study finding has indicated that the level of Sox-2 expression may be a useful tumorigenic and prognostic biomarker because it correlates to the 2-tier grades but not dog breeds.

Abstract Background While lymphadenectomy of metastatic lymph nodes (LNs) has been associated with improved outcome, the clinical utility of prophylactic lymphadenectomy in dogs with stage I cutaneous mast cell tumors (cMCTs) remains a controversial topic. To assess the therapeutic role of lymphadenectomy of uninvolved regional LNs, the long-term outcome of cMCT-bearing dogs with cytologically negative and surgically unresected regional LNs (observation only, OO) was compared with that of dogs with surgically resected and histologically negative regional LNs (prophylactic regional lymphadenectomy, PRL). Results A retrospective analysis of 64 dogs with a low-grade, completely resected stage I cMCT was performed: 35 (54.7%) dogs were subjected to OO and 29 (45.3%) underwent PRL. Dogs were monitored for a median of 813 and 763 days in the OO group and PRL group, respectively. The number of dogs undergoing MCT progression was significantly higher in the OO group (P = 0.028) and curve comparison revealed a tendency to a better time to progression in the PRL group (P = 0.058). No significant difference in survival time (P = 0.294) was observed between dogs in the OO and PRL groups. Conclusions Our results showed that lack of immediate lymphadenectomy was associated with a higher risk for tumor progression. This preliminary judgement, reinforced by the findings that lymphadenectomy was well tolerated in all cases, and that histopathology provides the definitive assessment of the nodal pathological status, may suggest that prophylactic lymphadenectomy is indicated in the management of stage I MCTs. Larger prospective studies are warranted for generating clinical evidence of this latter hypothesis.

Simple Summary: Congenital mast cell tumor is an uncommon disease in both human and veterinary medicine. In cattle, usually, such anomalies are not further investigated at the molecular genetic level, mainly because of a lack of resources and diagnostic tools and the low value and short life expectancy of the affected animals. Here we reported the clinical, pathological and genetic findings of a Holstein calf that had multiple cutaneous and visceral poorly differentiated embryonal mast cell tumors consistent with a form of congenital mast cell tumor. Whole-genome sequencing identified a single X-linked recessive protein-changing variant in the PLP2 gene that was unique to the affected male calf and its dam and absent in a representative control cohort. Given the rarity of the identified variant, its predicted deleterious effect and the known function of proteolipid protein 2, a small transmembrane lipoprotein associated with skin cancer, we proposed a novel candidate gene associated with mast cell tumors. Congenital tumors occur infrequently in cattle. The aim of this study was to detail the clinicopathological phenotype of a Holstein calf with a congenital mast cell tumor and to identify the genetic cause by a whole-genome sequencing (WGS) trio-approach. An 18-day-old male Holstein calf was clinically examed and revealed multifocal, alopecic, thick and wrinkled skin lesions over the entire body. At 6 months of age, the general condition of the calf was characterized by retarded growth, poor nutritional status, and ulceration of the skin lesions. Histopathological examination revealed a primary cutaneous, poorly differentiated embryonal mast cell tumor with metastases in the lymph nodes and liver. Genetic analysis revealed a private X-linked variant in the PLP2 gene (chrX:87216480C > T; c.50C > T), which was present only in the genomes of the case (hemizygous) and his mother (heterozygous). It was absent in the sire as well as in 5365 control genomes. The identified missense variant exchanges the encoded amino acid of PLP2 at position 17 (p.Thr17Ile), which is classified as deleterious and affects a protein that plays a role in tumor growth and metastasis. Therefore, we suggested that the detected PLPL2 variant could be a plausible cause for this congenital condition in the affected calf. [ABSTRACT FROM AUTHOR]

Simple Summary: The African dormice, also known as micro squirrels, are now becoming more and more popular as they present as laboratory animals, exhibited animals, or pets. However, we know very little about the diseases in these tiny rodents, such as tumors or infectious microorganisms. A 3-year-old, male African dormouse was taken to the veterinary clinic after showing vomiting and anorexia. A stomach lesion was noted through imaging examinations. The patient died after being treated for 2 months. The veterinary pathologist diagnosed the lesion as a gastric mast cell tumor, cancer occurs mostly in cats and rarely in other animals. This is the first time that a mast cell tumor is diagnosed in an African dormouse. We suggest that the mast cell tumor in digestive tracts should be listed in the differential diagnoses when an elder African dormouse or other small rodent shows chronic digestive signs. Mast cell tumors (MCTs) are well-known neoplasms derived from either mucosal or connective tissue mast cells. While well studied in several domestic species, MCTs are rarely documented in rodents. A three-year-old, male African dormouse (Graphiurus sp.) presented with a history of vomiting and anorexia for 3 months. Sonography revealed thickened gastric mucosa and hyperperistalsis. The patient died after receiving symptomatic treatment for 2 months. At necropsy, locally extensive, pale, thickened mucosal foci obscuring the first half of the stomach lumen was noted. Histological examination revealed moderately polymorphic, round, oval to spindle cells with amphophilic cytoplasmic granules infiltrating the mucosa to tunica muscularis, with moderate numbers of eosinophils. The mucosa was severely ulcerated with the proliferation of granulation tissue. The granules in most tumor cells exhibited metachromasia with the toluidine blue stain. Neoplastic cells revealed positive membranous immunoreactivity to KIT. Herein, we report the first case report of MCT in dormouse but also the first gastrointestinal MCT in a rodent species. [ABSTRACT FROM AUTHOR]

Simple Summary: Mast cell tumors (MCTs) are one of the most common skin tumors in dogs with variable clinical behavior ranging from benign lesions to those causing widespread metastasis. Prognostic factors have been intensively studied in cutaneous MCTs but are less commonly investigated in subcutaneous MCTs as the majority are benign. Activating mutations in exons 8 and 11 of c-kit, a gene that regulates proliferation and differentiation of mast cells, occur commonly in canine cutaneous MCTs and are strong predictors of prognosis. c-kit mutations have rarely been reported in subcutaneous MCTs. The goal of this study was to identify the prevalence of c-kit mutations in exons 8 and 11 in 216 canine subcutaneous MCTs and to investigate their association with other prognostic factors, including mitotic count, histologic grade, KIT pattern and proliferation markers. We detected c-kit mutations in exons 8 and 11 in 23 (10.6%) and 12 (5.56%) subcutaneous MCTs, respectively. c-kit mutations in exon 11 were associated with histologic high grade and a high mitotic count, suggesting that these parameters can predict the biological behavior of subcutaneous MCTs in a similar manner as in their cutaneous counterparts. The prognostic significance of internal tandem duplication (ITD) mutations in exons 8 and 11 of c-kit has been well-described for canine cutaneous mast cell tumors (MCTs), but c-kit mutations have rarely been reported in subcutaneous MCTs. The objective of this study was to identify the prevalence of ITD mutations in exons 8 and 11 of c-kit in canine subcutaneous MCTs and to investigate its association with histologic grade, KIT pattern, and proliferation markers. ITD mutations in exons 8 and 11 of c-kit, mitotic count, Ki67 index, AgNOR number, Ki67xAgNOR score, KIT pattern, and histologic grade (two-tier system) were retrospectively recorded for 216 dogs with subcutaneous MCTs. ITD mutations in exons 8 and 11 of c-kit were detected in 23 (10.6%) and 12 (5.56%) subcutaneous MCTs, respectively. Exon 11 mutations were significantly associated with Kiupel high grade (p < 0.001) and increased mitotic count (p < 0.001) compared to subcutaneous MCTs with no mutations in exons 8 or 11 (p = 0.002) or subcutaneous MCTs with a mutation in exon 8 (p = 0.001). There was no significant association of either c-kit mutation with KIT patterns or proliferation activity. This study identified a higher prevalence of ITD mutations in exons 8 and 11 of c-kit in subcutaneous MCTs than previously reported. Like their cutaneous counterpart, subcutaneous MCTs with exon 11 mutations were more likely to be histologically high grade and have a higher mitotic count, whereas such associations were not observed in subcutaneous MCTs with exon 8 mutations. [ABSTRACT FROM AUTHOR]

Simple Summary: Mast cell tumor is one of the most common cutaneous tumors in dogs, representing 16–21% of all cutaneous tumors. Clinical staging is a fundamental step in the patients' assessment, and it is considered essential to further refine the prognosis and to establish an ad hoc therapeutic plan. The recommended staging work-up includes a basic laboratory database, fine needle aspiration of the expected tumor draining lymph node/s, and diagnostic imaging with fine needle aspiration of the liver and spleen. The aim of this retrospective study was to investigate the incidence, at presentation, of hepatic and splenic metastases in dogs affected by low-grade cutaneous mast cell tumor referred for further investigations (Patnaik grade I–II, Kiupel low-grade). Only 1 out of 136 dogs had the presence of visceral metastases at diagnosis, suggesting that the prevalence of visceral metastases in low-grade cutaneous mast cell tumor is extremely low and that cytology of visceral organs may not represent an essential step in the clinical staging work-up in these dogs. Clinical staging is a fundamental step in the clinical assessment of canine cutaneous mast cell tumor (cMCT), and it is recommended to evaluate the tumor draining lymph node (eTDLN), perform diagnostic imaging, and fine needle aspiration (FNA) of the spleen and liver to determine the presence of metastatic disease, thereby refining the prognosis. The aim of this retrospective study was to evaluate the prevalence of splenic and hepatic involvement in newly diagnosed canine low-grade cMCT (Patnaik grade I–II, Kiupel low-grade). Medical records of dogs that underwent a clinical staging work-up and surgical excision for a low-grade cMCT between December 2019 and December 2021 were reviewed at five veterinary centers. Only dogs with a histological diagnosis of low-grade cMCT, FNA or histology of the eTDLN, FNA of the spleen and liver, and one year of follow up were included. One hundred and thirty-six dogs met the inclusion criteria. Only 1 out of 136 dogs (0.7%) had the presence of visceral metastases at diagnosis, suggesting that the prevalence of visceral metastases in low-grade cMCT is extremely low. The results of this study are consistent with previous literature and suggest that after a diagnosis of low-grade cMCT, cytology of visceral organs may not represent an essential step in the clinical staging work-up. [ABSTRACT FROM AUTHOR]

Lymph node (LN) metastasis in canine mast cell tumor (MCT) can affect prognosis and postsurgical treatment recommendations; however, routine histological single-section examination may underestimate the incidence of metastases. This prospective study aimed at determining whether longitudinal step-sectioning of the entire LN allows for a more reliable detection of metastases. Dogs with MCT undergoing resection of the primary tumor and regional lymphadenectomy were enrolled. Formalin-fixed LNs were bisected longitudinally, both halves were embedded in paraffin and histological sections prepared at 200 μm steps. The nodal mast cells were classified according to the Weishaar classification. First-section evaluation (FSE; ie, examination of the first section obtained from the blocks) and whole LN step-section evaluation (SSE) were compared. Fifty-eight LNs were included. The median number of sections per LN was 6 (range, 3–28). FSE with toluidine blue (TB) revealed 27 (47%) nonmetastatic (HN0), 14 (24%) premetastatic (HN1), 9 (15%) early metastatic (HN2), and 8 (14%) overtly metastatic (HN3) LNs. SSE with TB resulted in upgrading the LN status in 2 cases (HN2 to HN3; HN0 to HN1). Evaluation of the first section plus an additional step-section resulted in 100% accuracy. Compared with SSE with TB, the accuracy of FSE with HE was 98% for HN3 LNs and 74% for HN2 LNs. FSE appears to reliably allow for the detection of LN metastasis in MCT, although examination of a further parallel section at a 200 μm step may increase the accuracy. A metachromatic stain is recommended for the identification of early metastases. [ABSTRACT FROM AUTHOR]

Background: Cell free DNA, in the form of nucleosomes, is released into circulation during apoptosis and necrosis in a variety of diseases. They are small fragments of chromosomes that are composed of DNA wrapped around a histone core made of four duplicate histone proteins forming an octamer. The nucleosome compartment is a relatively uninvestigated area of circulating tumor biomarkers in dogs. The objectives of this study were to quantify and better characterize nucleosome concentrations in 528 dogs with various common malignancies and compare them to 134 healthy dogs. Results: The sensitivity of increased circulating nucleosome concentrations for the detection of cancer in all dogs was 49.8% with a specificity of 97% with an area under the curve of 68.74%. The top 4 malignancies detected by the test included lymphoma, hemangiosarcoma, histiocytic sarcoma and malignant melanoma. The malignancies least likely to be detected were soft tissue sarcomas, osteosarcoma and mast cell tumors. Conclusions: A variety of tumor types may cause increased nucleosome concentrations in dogs. Tumors of hematopoietic origin are most likely to cause elevations and local tumors such as soft tissue sarcomas are least likely to cause elevations in plasma nucleosome concentrations. [ABSTRACT FROM AUTHOR]

Simple Summary: Lipopolysaccharide (LPS) derived from intestinal bacteria is linked to long-lasting inflammation that contributes to the development of intestinal cancer. While much research has been performed on the interplay between LPS and intestinal immune cells, little is known about how LPS influences intestinal epithelial cell structure and function. In this study, we investigated the effects of LPS on the proliferation and function of genes in intestinal organoids derived from dogs with gastrointestinal diseases, including inflammatory bowel disease (IBD) and intestinal mast cell tumor. The goal of this study was to evaluate how LPS affects signaling pathways in intestinal epithelial cells to influence development of a pro-tumor-like environment. Using an ex vivo model system, LPS incubation of organoids activated cancer-causing genes and accelerated the formation of IBD organoids derived from the small and large intestines. In brief, the crosstalk that occurs between the LPS/TLR4 signal transduction pathway and several different metabolic pathways, including primary bile acid biosynthesis and secretion, peroxisome, renin-angiotensin system, glutathione metabolism, and arachidonic acid pathways, may play a prominent role in the development of chronic intestinal inflammation and intestinal cancer. Lipopolysaccharide (LPS) is associated with chronic intestinal inflammation and promotes intestinal cancer progression in the gut. While the interplay between LPS and intestinal immune cells has been well-characterized, little is known about LPS and the intestinal epithelium interactions. In this study, we explored the differential effects of LPS on proliferation and the transcriptome in 3D enteroids/colonoids obtained from dogs with naturally occurring gastrointestinal (GI) diseases including inflammatory bowel disease (IBD) and intestinal mast cell tumor. The study objective was to analyze the LPS-induced modulation of signaling pathways involving the intestinal epithelia and contributing to colorectal cancer development in the context of an inflammatory (IBD) or a tumor microenvironment. While LPS incubation resulted in a pro-cancer gene expression pattern and stimulated proliferation of IBD enteroids and colonoids, downregulation of several cancer-associated genes such as Gpatch4, SLC7A1, ATP13A2, and TEX45 was also observed in tumor enteroids. Genes participating in porphyrin metabolism (CP), nucleocytoplasmic transport (EEF1A1), arachidonic acid, and glutathione metabolism (GPX1) exhibited a similar pattern of altered expression between IBD enteroids and IBD colonoids following LPS stimulation. In contrast, genes involved in anion transport, transcription and translation, apoptotic processes, and regulation of adaptive immune responses showed the opposite expression patterns between IBD enteroids and colonoids following LPS treatment. In brief, the crosstalk between LPS/TLR4 signal transduction pathway and several metabolic pathways such as primary bile acid biosynthesis and secretion, peroxisome, renin–angiotensin system, glutathione metabolism, and arachidonic acid pathways may be important in driving chronic intestinal inflammation and intestinal carcinogenesis. [ABSTRACT FROM AUTHOR]

A dog underwent lung lobectomy for removal of a mass. Histopathology was consistent with narrow resection of a mast cell tumor. Postoperative pneumothorax was successfully treated using autologous blood pleurodesis. Progression of disease despite adjunctive treatment with several chemotherapetutic agents and radiation therapy resulted in euthanasia approximately 4 months postoperatively. [ABSTRACT FROM AUTHOR]

Abstract Background Nephrotic syndrome (NS) is rare in dogs and is characterized by concurrent clinical findings of proteinuria, hyperlipidemia, hypoalbuminemia, and edema. NS has been reported in humans receiving tyrosine kinase inhibitors (TKI) and in dogs receiving masitinib. This is the first report of NS in a dog receiving toceranib phosphate. Case presentation An 8-year-old, female, spayed Labrador retriever was diagnosed with a 10 cm mast cell tumor on the left lateral abdomen. After completion of a 12-week vinblastine and prednisone protocol, she began treatment with toceranib phosphate (2.6 mg/kg by mouth, every other day). Proteinuria was documented prior to starting toceranib. On day 426 after diagnosis (day 328 of toceranib phosphate treatment), the dog was evaluated for diarrhea, lethargy and anorexia. On physical examination, dependent edema was noted on the ventral chest and abdomen, and sterile neutrophilic inflammation was aspirated from a 2.3 cm splenic nodule. The following laboratory values were reported: albumin

Simple Summary: Skin and subcutaneous tumors are among the most frequent neoplasms in dogs and cats. We studied 51 samples of canine and feline skin, lipomas, soft tissue sarcomas, and mast cell tumors using a multimodal approach based on optical coherence tomography and Raman spectroscopy. A supervised machine learning algorithm detected malignant tumors with the sensitivity and specificity of 94% and 98%, respectively. The proposed multimodal algorithm is a novel approach in veterinary oncology that can outperform the existing clinical methods such as the fine-needle aspiration method. As in humans, cancer is one of the leading causes of companion animal mortality. Up to 30% of all canine and feline neoplasms appear on the skin or directly under it. There are only a few available studies that have investigated pet tumors by biophotonics techniques. In this study, we acquired 1115 optical coherence tomography (OCT) images of canine and feline skin, lipomas, soft tissue sarcomas, and mast cell tumors ex vivo, which were subsequently used for automated machine vision analysis. The OCT images were analyzed using a scanning window with a size of 53 × 53 μm. The distributions of the standard deviation, mean, range, and coefficient of variation values were acquired for each image. These distributions were characterized by their mean, standard deviation, and median values, resulting in 12 parameters in total. Additionally, 1002 Raman spectral measurements were made on the same samples, and features were generated by integrating the intensity of the most prominent peaks. Linear discriminant analysis (LDA) was used for sample classification, and sensitivities/specificities were acquired by leave-one-out cross-validation. Three datasets were analyzed—OCT, Raman, and combined. The combined OCT and Raman data enabled the best sample differentiation with the sensitivities of 0.968, 1, and 0.939 and specificities of 0.956, 1, and 0.977 for skin, lipomas, and malignant tumors, respectively. Based on these results, we concluded that the proposed multimodal approach, combining Raman and OCT data, can accurately distinguish between malignant and benign tissues. [ABSTRACT FROM AUTHOR]

Glucocorticoid administration is a common clinical practice that attempts to decrease the inflammation associated with and improve the resectability of canine mast cell tumors (MCTs). However, the impact of neoadjuvant glucocorticoids on the histological features and proliferation indices of canine MCTs is unknown. The objective of this study was to evaluate changes in tumor grade, mitotic count, Ki67, AgNOR, and AgNORxKi67 scores following short-course anti-inflammatory neoadjuvant prednisone in canine patients with MCTs. This was a prospective single-arm pilot study. Client-owned dogs with treatment-naïve cytologically confirmed MCTs were enrolled. Patients underwent an initial incisional biopsy followed by a 10–14-day course of anti-inflammatory prednisone and surgical resection. All histological samples were randomized, masked, and evaluated by a single pathologist. Unstained paired pre- and post-treatment samples were submitted to a commercial laboratory for Ki67 and AgNOR immunohistochemical analysis. There were 11 dogs enrolled with 11 tumors. There were no statistical differences between the pre- and post-treatment histological parameters of mitotic index, Ki67, AgNOR, or Ki67xAgNOR. There were no clinically significant alterations between pre-treatment and post-treatment in the assignment of tumor grades. A short course of anti-inflammatory prednisone does not appear to alter the histological parameters that affect grade determination or significantly alter the proliferation indices in canine MCTs. [ABSTRACT FROM AUTHOR]