Search

Background: Hepatic tumors of primary origin account for 0.6% to 2.9% of cases in canine species, less common than hepatic metastases. The hepatic tumors are divided into hepatocellular tumors, neuroendocrine tumors, bile duct tumors or cholangiocarcinomas, and mesenchymal tumors. Cholangiocarcinomas, are classified according to their origin, being intrahepatic, extrahepatic, or gallbladder type. Cholangiocarcinomas are considered rare in dogs and cats with a ratio of 29% to 71% compared to hepatocellular carcinomas, accounting for 9% of the hepatic tumors. The present study aims to describe a case of cholangiocarcinoma in a bitch, focusing on the diagnostic approach. Case: A 10-year-old castrated bitch Poodle was attended presenting hypoglycemia and seizure crisis. The patient had previous exams of hemogram and serum biochemical profile, showing a discrete increase of the hepatic enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST), besides hypoglycemia. Previous ultrasound exam revealed the presence of a hepatic mass located between the right and square lobes, immeasurable, and significant splenomegaly. Abdominal palpation revealed the presence of immeasurable abdominal formation of undetermined origin. Abdominal computerized tomography (CT), glycemic curve, and insulin dosage were requested. Tomography exam showed an increase in hepatic volume with the presence of a heterogeneous formation in the right lateral lobe topography; increase in spleen dimensions and the presence of multiple nodules; and the presence of a nodule in the right lung, at the caudal thoracic region. The glycemic curve showed acute variations, and insulin dosage was between normal values. The animal was referred for surgery, as in abdominocentesis, it was observed the presence of hemorrhagic fluid, confirming active bleeding by ultrasonography. The owners chose for euthanasia. In the post-mortem evaluation the main lesion was confirmed of hepatic origin, with a massive, irregular, cavitary presentation, involving multiple hepatic lobes, and a single nodule was observed in the right caudal lobe of the right lung. Histopathological evaluation was considered inconclusive. Immunohistochemistry was performed and the association of the immunohistochemical profile with the morphological characteristics indicated diagnosis of cholangiocarcinoma. Discussion: The related symptomatology, in hepatic neoplasms, is generally considered non-specific, with reports of lethargy, vomiting, dyspnea, anorexia and weight loss, however, the dog in this study presented a unique manifestation of hypoglycemia and one episode of convulsive crisis resulting from it. The clinical manifestation observed was extremely unspecific making initial diagnosis difficult. The ultrasonographic examination was effective in evidencing the abdominal mass. In addition, abdominal CT was also performed, which confirmed the hepatic origin, detailing the macroscopic aspect. Biochemical analyses of ALT and AST showed a discrete increase. Biochemical changes may occur in dogs with hepatic neoplasms, although they are not specific. Functional pancreatic beta-cell tumors producing insulin are the most common cause of paraneoplastic hypoglycemia, although in the case the insulin dosage was within normal limits. In cases of nonislet cell tumor the mechanism is frequently associated with the production of insulin-like growth factor (IGF). In most cases the definitive diagnosis of cholangiocarcinoma can be obtained by histopathological examination, although in the present report the result obtained was inconclusive, requiring an immunohistochemical examination. Due to the aggressive and metastatic character of this neoplastic type, early detection becomes extremely important in order to maximize therapeutic chances, however, diagnosis may be difficult. [ABSTRACT FROM AUTHOR]

Background: The most common primary brain neoplasm is meningioma. Dolichocephalic breeds are predisposed and there is no sexual predilection. Clinical signs depend on the location and size of the tumor and have a progressive course. Primary treatement includes surgery, radiotherapy or both. This study aimed to describe the treatment of a dog with suspected intracranial meningioma with definitive radiotherapy, which resulted in significant clinical improvement and prolonged survival. Case: A 9-year-old Shetland Shepherd bitch was diagnosed with a head tilt to the left side that progressed over a few weeks. She previously received corticosteroid therapy, which resulted a clinical improvement that worsened after treatment was discontinued. Computed tomography revealed an extra-axial brain mass in the caudal fossa, lateralized to the right, welldelimited, and measuring approximately 1.5 × 1.4 × 1.7 cm, suggestive of intracranial meningioma. The patient was treated with radiotherapy using Cobalt-60 equipment, with 18 daily fractions of 2.5 Gy at a total dose of 45 Gy using parallel and opposite technique fields. A new tomography performed 30 days after treatment showed a remission of 85% of the initial brain mass measuring approximately 0.9 × 1.0 × 0.5 cm, as well as complete resolution of the clinical signs initially presented. After 14 months, the patient presented with signs of lethargy and ataxia and was medicated with hydroxyurea at a dose of 50 mg/kg 3 times a week and corticosteroid therapy. However, the patient’s neurological condition deteriorated, and she was subjected to reirradiation using the same protocol used previously, which resulted in clinical improvement and a 54% reduction in tumor volume on magnetic resonance. As a late side effect, only permanent alopecia in the irradiated region was observed. The patient died of disease 330 days after the second course of radiotherapy, with a total survival time of 1087 days. Discussion: Meningiomas are extra-axial neoplasms of the central nervous system that grow inside the dura mater. The literature shows that meningiomas are more common in dolichocephalic races with a mean age of 9 years, which supports our findings. Meningiomas most commonly affect the cortical thalamus and cerebellopontine region in dogs, which are normally associated with vestibular symptoms, as seen in this case. Diencephalic damage can result in vestibular signals since the thalamus functions as a relay station for vestibular afferent stimuli that are relayed to the cerebral cortex. In addition to the vestibular syndrome, common clinical signs associated with meningiomas in dogs include seizures, behavioral changes, and walking in circles, which are frequently misinterpreted due to tumor-induced side effects, such as cerebral edema, obstructive hydrocephalus, and cerebral hernia. Advanced imaging techniques should be used to diagnose intracranial neoplasms. In this case, computed tomography was critical for diagnosis and treatment planning. Meningioma treatment may comprise palliative measures, surgery, and radiotherapy. Radiotherapy as a single treatment can improve the quality of life with a decrease in clinical signs and a median survival time of approximately 250-536 days, as reported in the literature. Hydroxyurea can be a therapeutic option in inoperable cases and for patients with clinical limitations to undergo successive anesthesia during radiotherapy. Its most serious side effect is progressive myelosuppression. It can cause temporary partial tumor remission and improvement in clinical signs. As previously stated, radiotherapy can be an effective primary treatment option for treating intracranial meningiomas in dogs, with significant improvement in neurological clinical signs and mild side effects. [ABSTRACT FROM AUTHOR]

Background: Urethral tumors are uncommon in canines, represented predominantly by transitional cell carcinoma, marked by aggressive behavior associated with short life expectancy. Definitive diagnosis is achieved by histopathological analysis. Surgery associated with chemotherapy is the main therapeutic alternative. The aim of this paper is to report a case of primary transitional cell carcinoma of the urethra in a bitch, submitted to surgical treatment associated with conventional adjuvant chemotherapy and metronomic chemotherapy, achieving survival of 21 months, to date. Case: A 12-year-old bitch mixed breed was admitted at the Veterinary Hospital of Federal Rural University of Rio de Janeiro (UFRRJ), manifesting hematuria and urinary incontinence for one month. Physical examination indicated that vital parameters were within normal limits. Laboratory tests of blood count and serum biochemistry, urinalysis, culture, urinary antibiogram, and abdominal ultrasound were performed. The ultrasound image suggested a neoplastic urethral process. Because of the suspicion of neoplasm, a thoracic X-ray was performed, showing no evidence of metastasis. Computed tomography (CT) of the abdominal region was performed, revealing an expansive lesion in the urethra with loss of definition of the walls and urethral lumen extending to the level of the pelvic floor, measuring about 2.9 x 1.4 x 1.2 cm. After preanesthetic exams, the animal underwent resection and surgical anastomosis of the affected urethral region. The sectioned tissue was sent for histopathological analysis, with diagnosis of transitional cell carcinoma. Adjuvant chemotherapy was performed using carboplatin at a dose of 250 mg/m², intravenously, every 21 days for 6 sessions. After completing the protocol, abdominal ultrasonography was performed again, which showed a cicatricial process in the urethral region of the surgical excision, with no sign of tumor recurrence. A metronomic chemotherapy protocol was then started with cyclophosphamide at a dose of 15 mg/m², daily for 6 months, with periodic oncological follow-up. At the end of the period, the animal remained under periodic follow-up with ultrasound exams performed at 2-month intervals, and has been free from recurrence for 21 months until now. Discussion: Urethral neoplasms account for 0.5 - 2% of all canine tumors, and are represented mostly by transitional cell carcinomas. Clinical signs of urinary obstruction and hematuria are the most common, as reported in the patient in question. The definitive diagnosis is by histopathological examination. However, imaging tests such as computed tomography are important in the initial investigation and surgical planning. The indicated treatment is surgical resection of the mass with subsequent adjuvant chemotherapy or radiotherapy. The chemotherapy protocol associating cisplatin and piroxicam can achieve remission rates of 70%, but this association has a high nephrotoxic effect. In the present case, cisplatin was replaced by carboplatin in order to reduce the nephrotoxic effects of chemotherapy. The metronomic protocol using cyclophosphamide was used as maintenance therapy, at the end of the conventional chemotherapy protocol. Survival achieved was longer than that described in the literature in cases of transitional cell carcinomas in the urethral region. Therefore, multimodal therapy using surgery associated with conventional and metronomic chemotherapy, is an option in canines with urethral carcinoma. [ABSTRACT FROM AUTHOR]

Background: Canine transmissible venereal tumor (TVT) is one of the most common canine neoplasms in Brazil. Lesions develop mainly in the genital tissue and less frequently in other areas, in the extragenital form. Metastasis is rare, and the disease progression depends on the patient’s immune status. The treatment of choice is chemotherapy with vincristine sulfate, considered an effective and safe modality. The present work describes the first case of extragenital TVT in the larynx with pulmonary metastasis at the time of diagnosis. Case: An approximately 4-month-old mixed-breed bitch was attended manifesting acute clinical respiratory signs. The patient had been rescued from the street 2 months beforehand. Physical examination revealed pale mucous membranes and crackling pulmonary auscultation. Thoracic radiography was performed in 3 projections, showing multiple nodules in the lung parenchyma, followed by cytopathological examination using fine needle puncture guided by thoracic ultrasound, confirming the diagnosis of TVT. Considering the cytological finding and the absence of primary tumor lesions in the genital, oral, cutaneous or nasal regions, endoscopy was performed in order to locate a possible primary focus. The exam revealed a small erythematous tumor with smooth and regular surface, measuring approximately 2.5 cm, located in the larynx, between the arytenoid cartilages. Chemotherapy was performed with vincristine sulfate with radiographic follow-up throughout the treatment. Full remission of the pulmonary and laryngeal nodules was achieved at the end of the protocol. The animal remained in complete remission for a period of 2 years. Discussion: TVT is more frequently observed in animals of active reproductive age, and rarely in animals under 1 year of age, as in the case described here. When considering extragenital lesions, the manifestation can be single or multiple, occurring more frequently in the cutaneous, oral and nasal forms. This case describes a laryngeal lesion with pulmonary involvement, without lesion in the genitalia or any other site. Cases of TVT in young and prepubescent animals, associated with extragenital involvement and aggressive behavior, similar to this case, have been described in literature, but never in this location. Literature suggests there is a relationship with the immune status of such patients, which do not have a well-developed immune system, facilitating disease progression. In these animals, transmission can be maternal, since in some cases the patient develops the disease without having contact with other animals except the mother. This form of transmission would facilitate the extragenital form in the oral cavity, airways and ocular region, related to licking, lactation and direct contact. Vincristine sulfate chemotherapy, considered the treatment of choice, was effectively used in this case, despite the atypical form. The TVT prognosis tends to be favorable, with the exception of the aggressive presentations with the presence of distant metastases. However, in the case described here, even though metastatic pulmonary nodules were present, complete remission was achieved, with survival exceeding 2 years. The development of TVT in the larynx is a rare form of the disease, and this report is possibly the first description of this tumor location. Thus, we highlight the importance of a complete investigation of the patient and of TVT as a differential diagnosis in this location. [ABSTRACT FROM AUTHOR]