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Benign and malignant nerve sheath tumors (NST) pose a major challenge in routine diagnostic anatomic pathology because of shared histomorphological features with other soft-tissue tumors (STT). As a result, NST are often diagnosed as STT, a broad category that encompasses various entities including perivascular wall tumors (PWT) and that represents approximately 15% of all skin tumors in dogs. Immunohistochemistry (IHC) can assist the identification of histologic subtypes of STT. This IHC pilot study applies various markers largely expressed by peripheral nerves to twelve benign and six malignant NST and determines the intratumoral protein expression of laminin, periaxin-1, Sox-10 and S-100 in the NST subtypes. Furthermore, this study assesses the usefulness of peripheral nerve markers applied to diagnostic work cases and demonstrates the relevance of laminin expression patterns, periaxin-1 and Sox-10 in assisting the differentiation of NST from other STT, in particular from PWT.

High survivin expression has been correlated with poor outcomes in several canine tumors but not in soft tissue tumors (STTs). Survivin is a target gene of the Wnt/β-catenin pathway, which is involved in human STT oncogenesis. Immunohistochemistry for survivin, β-catenin, and Ki-67 was performed on 41 canine perivascular wall tumors (cPWTs), and statistical associations of protein expression and histopathologic and clinical variables with clinical outcomes were investigated. Immunohistochemically, there was nuclear positivity (0.9%–12.2% of tumor cells) for survivin in 41/41 (100%), cytoplasmic positivity (0 to > 75% of tumor cells) for survivin in 31/41 (76%), nuclear positivity (2.9%–67.2% of tumor cells) for β-catenin in 24/41 (59%), and cytoplasmic positivity (0% to > 75% of tumor cells) for β-catenin in 23/41 (56%) of cPWTs. All tumors expressed nuclear Ki-67 (2.2%–23.5%). In univariate analysis and multivariate analysis (UA and MA, respectively), every 1% increase of nuclear survivin was associated with an increase of the instantaneous death risk by a factor of 1.15 [hazard ratio (HR) = 1.15; P =.007]. Higher nuclear survivin was associated with grade II/III neoplasms (P =.043). Expression of cytoplasmic survivin, nuclear and cytoplasmic β-catenin, and nuclear Ki-67 were not significantly associated with prognosis in UA nor MA. Tumor size was a significant prognostic factor for local recurrence in UA [subdistribution HR (SDHR) = 1.19; P =.02] and for reduced overall survival time in MA. According to UA and MA, a unitary increase of mitotic count was associated with an increase of the instantaneous death risk by a factor of 1.05 (HR = 1.05; P =.014). Nuclear survivin, mitotic count, and tumor size seem to be potential prognostic factors for cPWTs. In addition, survivin and β-catenin may represent promising therapeutic targets for cPWTs. [ABSTRACT FROM AUTHOR]

Introduction: Radiofrequency (RF) relieves chronic pain in humans, but it is unexplored in horses affected by chronic lameness. This study aims to describe the technique and the histological effects of ultrasound (US)-guided radiofrequency ablation (RFA) of palmar digital nerves (PDNs) in horse's fetlock and pastern, ex vivo. Methods: After assessing the US anatomy of lateral and medial PDNs in fetlock and pastern in vivo (n = 10 horses; 20 forelimbs), US-guided RFA was performed on these sites in cadaveric forelimbs (n = 10) applying four different settings with increasing invasiveness (n = 40 total treatments): 60°C, 6 min (GROUP LOW); 70°C, 4 min (GROUP MEDIUM); 90°C, 2 min (GROUP HIGH); 80°C, 8 min (GROUP VERY HIGH). Needle-tip-to-nerve proximity was assessed with US and methylene blue, injected through the port of the RF needle. Nerves were collected for microscopical assessment. Results: Transverse palmaro-lateral and palmaro-medial US images of fetlock and pastern detected PDNs consistently, close to the palmar digital artery. With in-plane US technique, RFA was performed at target in 31/40 cases, with significantly higher number of failures in fetlock (p = 0.008). PDNs histology identified thermal injury/coagulation with axonal degeneration and collagen homogenation. Nuclear smearing of arterial leyomyocytes was also observed. Nerve coagulation was significantly associated with treatment (p = 0.03) and needle-tip-to-nerve proximity (US distance: p = 0.009; blue distance: p = 0.04). Discussion: The PDNs were easily visualized and reached with the RF needle by US in-plane-guided technique. RFA produced axonal thermal damage and intensity-related coagulation effectiveness. To ensure effective nerve coagulation, it is crucial that the needle is accurately positioned in close proximity to the target nerve. Based on the histopathological findings, HIGH and VERY HIGH RFA treatments might be worth of being tested in vivo in clinical studies aimed at treating chronic lameness of the distal forelimb in horses. [ABSTRACT FROM AUTHOR]

This case report describes the clinical, dermoscopic and histopathological findings of three different neoplastic lesions (angiokeratoma, squamous cell carcinoma and multiple melanocytomas) and non-tumoral skin in a hairless Chinese crested dog following chronic sun exposure. The non-tumoral skin was characterized by "sunburn cells", collagen degeneration, dermal elastosis and fibrosis, described in most species as caused by UV light exposure. Cutaneous angiokeratomas have been rarely reported in the canine literature. In this particular case we consider a possible correlation with UV damage. [ABSTRACT FROM AUTHOR]

Simple Summary: Inflammatory mammary carcinoma (IMC) is the most aggressive and malignant type of mammary tumour, described in humans, dogs, and rarely in cats. This entity may clinically resemble an inflammation but is characterized by a fulminant clinical course, recurrence after surgery, with poor prognosis and survival rates. Cytology is rarely applied for the preliminary diagnosis of mammary tumours, given their complex or mixed morphology in dogs, and especially for IMC, where the diagnosis derives from the association of histopathology and clinical features. Therefore, the aim of this study was to describe cytological features of canine IMC and find possible cytological aspects allowing IMC specific diagnosis and differentiation from other mammary tumour types. Distinctive features of IMC included low cellular cohesiveness, ballooning aspect of some neoplastic cells, marked multinucleation, specific chromatin pattern, and occurrence of squamous metaplasia in some individualised cells or in cells in small groups. Thus, even without clinical information, IMC cytological features allow to suspect and/or to perform a diagnosis of IMC. The study highlights a relevant utility of cytological examination, from which both pathologists and clinicians could benefit, avoiding unnecessary treatments as IMC surgery is not curative. Background: Inflammatory mammary carcinoma (IMC) is the most aggressive and malignant type of mammary carcinoma. As in humans, canine IMC resembles mastitis clinically. However, IMC is highly aggressive with high incidence of metastases and common recurrence after surgery, leading to guarded prognosis and low survival rate. Given the complex morphology of canine mammary tumours, cytological examination is not performed routinely, and IMC diagnosis relies on the association of clinical features and histopathology. The purpose of this study is to describe the characteristics of canine IMC cytology, in an attempt to find possible cytological features that allow differentiation of IMC from other mammary tumour types. Methods: We analysed preoperative cytological samples from 25 dogs with IMC, later confirmed by corroborating clinical and histopathological examinations. Results: Distinct cytological features of canine IMC included scarce cellular cohesiveness, ballooning aspect of neoplastic cells, frequent multinucleation, irregularly dispersed and ropy chromatin pattern, and squamous metaplasia in some individualised cells or those in small groups. Conclusions: Our results indicate that cytological examination can contribute to the diagnosis of IMC and might help differentiate it from other mammary carcinomas, even when clinical data is not available, which is common in cytological routine. [ABSTRACT FROM AUTHOR]

Proliferative, lymphocytic, infundibular mural folliculitis and dermatitis have been reported in six female Labrador retrievers from North America. This is the first report of the disease outside North America, describing the clinical and histopathological diagnosis and dermoscopic aspect of the verrucous plaques, treatment and co‐morbidities in a female Labrador retriever dog. [ABSTRACT FROM AUTHOR]

Simple Summary: Hemangioendothelioma is an uncommon neoplasm that affects both humans and animals. Its clinical course is unclear. This report describes the first case of hepatic epithelioid hemangioendothelioma in a dog. The clinical and microscopic characteristics of this neoplasm overlap with those described in humans; therefore, this report can be informative as a spontaneous animal model but, at the same time, also useful for veterinary progress in diagnostic orientation and therapeutic treatment. A 5-year-old spayed female Breton dog was referred for a thyroid nodule. A total body CT scan evidenced multifocal hepatic nodules. Cytological liver samples were hemodiluted and non-diagnostic. Following a thyroidectomy, the histology was consistent with a follicular-compact thyroid carcinoma. On laparoscopy, most hepatic lobes had multifocal dark-red nodules that were biopsied for histology. Microscopically, the hepatic parenchyma in the nodules was substituted by blood channels lined by bland spindle cells but adjacent to epithelioid neoplastic cells, single or in clusters, embedded in a moderate amount of edematous collagen matrix. These cells had optically empty cytoplasmic space, occasionally containing erythrocytes (microlumina). Spindle and epithelioid cells expressed membranous-to-cytoplasmic CD31 and FVIII-RA consistent with endothelial origin. Based on morphology and immunolabelling, a hemangioendothelioma with epithelioid differentiation was diagnosed. Lesions in the liver were initially stable, showing progression with time. The dog was alive with no systemic clinical signs 36 months after laparoscopy. [ABSTRACT FROM AUTHOR]

Background: Primary cutaneous lymphoma represents 0.2%–3% of all feline lymphomas, with nonepitheliotropic lymphomas being the most common. In humans and dogs, subcutaneous panniculitis‐like T‐cell lymphoma (SPTCL) is a primary nonepitheliotropic lymphoma with a T‐cell phenotype developing in the subcutis and often mimicking inflammation. Objective: The aim of this report is to describe pathological, phenotypical and clonal features of SPTCL in cats. Animals: Six cats with SPTCL were included in this study. Materials and Methods: Skin biopsies were formalin‐fixed, routinely processed and stained. Histological and immunohistochemical investigation for anti‐CD18, CD204, CD79a, CD20, CD3, FeLVp27and FeLVgp70 and clonality assessment were performed. Results: Four male and two female domestic shorthair cats, mean age 11.2 years, developed SPTCL in the abdominal (three), inguinal (two) and thoracic (one) regions. Variably pleomorphic neoplastic lymphoid cells were present in the panniculus in percentages, expanding the septa (six of six) and extending into fat lobules in one of six cats. Tumours were associated with elevated numbers of neutrophils (five of six), lesser macrophages (six of six) and variable necrosis (six of six). Neoplastic cells expressed CD3+ (six of six), with clonal T‐cell receptor rearrangement detected in five of six cats. Conclusions and Clinical Relevance: This is the first description of SPTCL in cats. Lesions can be confused with panniculitis, leading to delay in diagnosis and therapy. Awareness of this neoplastic disease is relevant to avoid misdiagnoses and to gain greater knowledge about the disease in cats. [ABSTRACT FROM AUTHOR]

Copyright of Veterinary Dermatology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to the low frequency and the changes in diagnostic techniques and terminology during the last few years, only little clinical information is available on splenic stromal sarcoma (SSS). This multi‐institutional study aimed at gathering clinical cases of SSS in dogs and investigates their clinical behaviour, as well as analyse possible clinicopathological prognostic factors, including the use of adjuvant therapy. Dogs with a histologically confirmed SSS that underwent splenectomy were retrospectively included. To be included in the study, either FFPE tissue blocks or multiple tissue sections had to be available for histopathologic and immunohistochemical revision. Clinical and pathological variables, along with adjuvant therapy data, were collected. Cumulative incidence of metastatic disease was analysed through univariate and bivariate analyses. The impact of adjuvant chemotherapy on metastasis incidence and survival was assessed, considering an estimated propensity score. A total of 32 dogs were included. Among them, 22 developed metastases with an incidence of 37.5%, 59.38%, and 65.94% at 6, 12, and 24 months, respectively. Univariate analysis identified mitotic count, total scoring, and necrosis as prognostic factors. In bivariate analysis, mitotic count remained prognostic. The administration of adjuvant chemotherapy did not have an impact on metastasis incidence or survival time. The study found that dogs with SSSs are at high risk of metastasis, although a small subgroup may experience longer survival after splenectomy. Mitotic count was the only variable having a reliable prognostic impact. Adjuvant chemotherapy did not appear to decrease the incidence of metastasis or prolong survival in these dogs. [ABSTRACT FROM AUTHOR]

Copyright of Veterinary Dermatology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Veterinary Cancer Guidelines and Protocols (VCGP) group has developed guidelines for developing, reporting, and validating histologic tumor grading systems. These guidelines aim to standardize tumor evaluation in order to improve the care of animals with cancer. The grading systems should be reproducible, relevant to prognosis, and realistic in terms of applicability in a routine diagnostic setting. The VCGP group encourages collaboration from various disciplines and emphasizes the importance of standardized clinical outcomes and statistical assessment. The guidelines also suggest comparing histologic grade with other assays and encourage the publication of grading systems in peer-reviewed journals with sufficient details for replication and validation. Validation studies should be conducted before implementing the grading system on clinical cases. [Extracted from the article]

Perivascular wall tumors (PWTs) are common well-known canine mesenchymal tumors. The term PWT has not yet been applied to cats; only 2 cases of feline soft tissue hemangiopericytomas (HEPs) are available. In human medicine, sinonasal HEP-like tumor/glomangiopericytoma (SHPCL/GP) and intranasal solitary fibrous tumor (SFT) are well-known mesenchymal tumors with staghorn vasculature and low malignant potential; however, these entities have not been described in small animals. We describe here the pathologic and immunohistochemical features of 2 cases of feline intranasal mesenchymal tumors consistent with PWTs and resembling human SHPCL/GP (case 1), and human intranasal SFT (case 2). Both cats developed intranasal, unilateral, polypoid, expansile neoplasms with a mostly patternless growth of spindle cells, minimal stroma, and prominent staghorn vessels. The stroma was PAS negative, which excludes a glomus tumor. Immunohistochemistry identified diffuse vimentin and PDGFRβ expression. Case 1 was α-SMA positive (as is human SHPCL/GP); case 2 was negative (as is human intranasal SFT). Both tumors were incompletely excised, leading to recurrence in case 1. Case 2 was lost to follow up. To our knowledge, intranasal PWTs have not been reported previously in cats. The frequency of the lesions is not known, but awareness of these entities may assist in their recognition and better characterization in the future. [ABSTRACT FROM AUTHOR]