Neoplasmas testiculares em cães

Abstract

The main objective of this study was to review the biopsy protocols of canine testicular neoplasms over a period of 19 years, in order to characterize the prevalence and the clinical, macroscopic and histopathological aspects of these neoplasms. Parameters regarding the age, size and breed of the affected dogs were also established. Additionally, the objective was to report an uncommon case of a malignant Leydig cell tumor in a dog. Data regarding the breeds and ages of the affected male dogs and the clinical and macroscopic aspects were obtained from the biopsy reports of the Laboratório de Patologia Veterinária of the Universidade Federal de Santa Maria (LPV-UFSM) over a period of 19 years (2000 to 2018). Of the total number of biopsies received from male dogs, dogs with testicular neoplasms were counted, as well as the total number of neoplasms diagnosed in different organs in these dogs. The prevalence of dogs with testicular neoplasms was 213/1,900 cases, making up 11.2%. In 190/213 cases, paraffin blocks were available for reevaluation of neoplasms. Considering these 190 cases/dogs, a total of 220 neoplasms were diagnosed. The most frequent testicular tumors in the diagnostic routine were: seminomas (88/220), Leydig cell tumors (64/220), Sertoli cell tumors (61/220;) and the mixed germ-cell sex cord stromal tumor (MGSCT; 07/220). Large breeds had the highest number of cases (50/119), followed by small (47/119) and medium breeds (22/119). The ages among all dogs in this survey ranged from 10 months to 18 years. In some intratubular seminomas, it was possible to suggest two sites of neoplastic transformation of intratubular germ cells. Sertoli cell tumor was the most heterogeneous neoplasm in terms of cell shape and arrangement. Most dogs affected by Leydig cell tumors had the solid-diffuse and cystic-vascular types, while a smaller proportion of the tumors were formed by one of these patterns together with the pseudoadenomatous pattern. Through this study it was possible to evaluate the main aspects of canine testicular neoplasms and to categorize the breeds, sizes and age groups of dogs affected in the studied period. The histopathological reassessment made it possible to go into greater detail about the cell morphology of these neoplasms. The second article reports an unusual case of malignant Leydig cell tumor in a dog with cutaneous and lymph node metastasis and abdominal muscle infiltration. In dogs, malignant Leydig cell tumors are rare, with few reports in the international literature. The case reported in this study was observed in a six-year-old Beagle. The left testicle was completely obliterated by a firm, grayish-white mass. Under microscopy, neoplastic cells had abundant eosinophilic cytoplasm and little distinct cell boundaries. High degree of pleomorphism, atypical cells and abundant mitosis figures were observed. Through an immunohistochemical panel, it was possible to rule out other differential diagnoses. Thus, this report described a malignant interstitial cell tumor with disseminated metastases in a dog.