The aim of the present prospective-retrospective study was to evaluate the response of high-risk canine mast cell tumours (MCTs) to tyrosine kinase inhibitors (TKIs) and to correlate this with prognostic factors. A total of 24 dogs presented with macroscopic cutaneous MCTs at disease stage II or III, and therefore, at high-risk of associated mortality, were included in the study and treated with masitinib (n=20) or toceranib (n=4). A total of 12/24 dogs achieved an objective response and the overall survival (OS) for all subjects was 113 days. Dogs responding to treatment had a significant increase in OS compared to non-responders (146.5 days vs. 47 days, P=0.02). Internal tandem duplications in exon 11 of the c-kit gene were identified in 6/24 cases. Ki67, KIT immunolabelling and c-kit mutation did not provide information regarding prognosis or prediction of response to TKIs in this population. Initial response to TKIs appears to be the most reliable prognostic factor for survival duration.

A imuno-histoquímica pode ser aplicada na oncologia veterinária para a definição do imunofenótipo neoplásico, com possibilidades ilimitadas de utilização. A técnica baseia-se na identificação de antígenos "in situ", que podem apresentar valor prognóstico e terapêutico. A expressão de receptores de estrógeno e progesterona está diretamente relacionada ao melhor prognóstico para os neoplasmas mamários, enquanto a super-expressão do receptor KIT (CD117), proteínas Ki-67 (MIB-1), VEGF, CD31 e COX-2 podem ser associados à progressão tumoral para vários tipos histológicos. Essa associação possui valor preditivo em potencial, tendo em vista a possibilidade da utilização de bloqueadores específicos. Esta revisão tem como objetivo apresentar as possibilidades da utilização da imuno-histoquímica nos tumores de cães, visando à definição mais precisa do prognóstico e a indicação de tratamentos específicos para cada paciente.

No abstract

Background: Thymomas are epithelial neoplasms of the thymus, although lymphocyte infiltration is common. Histological features are not sufficient to define its biological behaviour, which is dependent of clinical criteria of invasiveness and resectability. Myasthenia gravis may happen as a paraneoplastic syndrome in up to 47% of canine thymomas. Thisarticle aims at reporting a case of thymoma associated with myasthenia gravis in a dog, emphasizing the morphological, phenotypical and therapeutical aspects.Case: A 7-year-old, male Labrador, was presented with a history of acute dyspnea and exercise intolerance. The physical examination revealed a “red-brick” mucousa, tachycardia and cardiac and pulmonar hypofonese. Chest radiographs revealed an area of increased radiopacity in the cranial mediastinum without a plane of separation to the heart. The eccodopplercardiogram exam identified a poorly delimited mass adjacent to the base of the heart, measuring 9.5x6.8cm. Computed tomographydemonstrated it as an expansive neoformation (9.5x6.5x7.8cm). Mass was removed through intercostal thoracotomy and the removed tissue was submitted to histopathology with a diagnosis compatible with type AB thymoma (mixed). Immunohistochemistry was positive for AE1/AE3 citokeratin in 90% of epithelial cells, confirming tumour origin. Tumour infiltrating lymphocytes were positive for CD79a (70%) and CD3 (20%). The proliferation index (Ki-67 imunolabeling) was 60%. About 45 days after surgery the patient was presented with generalized muscle weakness and regurgitation, with confirmed megaesophagus on chest X-ray. Treatment with pyridostigmine was initiated because of suspected myasthenia gravis, and complete remission of the neurological signs occurred within a month. A chemotherapeutic protocol with carboplatin wasthen instituted. After four sessions, a new thoracic radiograph revealed tumour recurrence in the cranial mediastinum. Therefore, metronomic chemotherapy was started sequentially with oral chlorambucil and firocoxib. Patient remained well for nine months when regurgitation and muscle weakness re-initiated, even with pyridostigmine treatment. New chestX-ray demonstrated increased tumour mass and the owner decided for euthanasia, resulting in a survival time of 368 days.Discussion: The prognosis of the thymoma depends on the histological type, clinical staging and presence of paraneoplastic syndromes. Due to the heterogeneity of the cases, there are not enough studies available to compare the animals submitted to different therapeutic modalities. In humans, when possible, and in the absence of metastases, complete surgical resection is the standard treatment followed by chemotherapy and/or adjuvant radiotherapy. In dogs, surgical resection of thymomasshould be considered, despite the invasiveness detected in imaging studies. The presence of paraneoplastic syndromes, such as myasthenia gravis, are commonly associated with worse prognosis, however, as evidenced in this case, pyridostigmine was useful in maintaining the neuromuscular function and patient´s quality of life, along with surgery and adjuvant chemotherapy, which probably contributed to the increase of the expectation of life. Further studies are necessary to evaluate the efficacy of adjuvant chemotherapy in maximum tolerated and metronomic dosage, for thymic neoplasms in dogs.Keywords: thymus, neoplasia, paraneoplastic syndrome, carboplatin, cyclophosphamide.

Pyometra is a common disease in intact female dogs and can cause glomerulopathy and tubular injury. This study aimed to evaluate kidney injury in female dogs with pyometra, as well as progression of the injury during treatment and the markers of this condition. This study analyzed 20 intact female dogs with both clinical and sonographic diagnosis of pyometra. Dogs were treated with intravenous fluids and antibiotics, and an ovariohysterectomy was performed. The following parameters were assessed at eight separate time points: blood pressure; serum creatinine, phosphorus, and urea levels; urinalysis and urinary biochemical parameters [urinary gamma-glutamyl transferase (uGGT) and urinary protein-to-creatinine ratio (UPCR)]; glomerular filtration rate (GFR); and urine output. All dogs showed some degree of kidney injury at the time of pyometra diagnosis. This was transient in most animals, resolving with treatment of the pyometra. Measurement of uGGT and UPCR identified renal parenchymal injury, helping to determine the prognosis of the animals analyzed in the present study.