The adrenal glands of 300 dogs, underwent to necropsy in the Laboratório de Patologia Veterinária at the Universidade Federal de Santa Maria (LPV/UFSM), were studied from March 2012 to June 2013. The collected tissues were fixed in 10% buffered formalin and sent to the routine histological processing in order to preparation and analysis of histological slides. Subsequently, it was reviewed the necropsy reports and the epidemiological data of the dogs which had the adrenal glands collected. Out of the 300 dogs examined, 82% had one or more adrenal lesions that were classified according to the pathogenesis and prevalence. The hyperplastic lesions were the most prevalent, comprising 91.5% of the cases, followed by degenerative (26%), circulatory (20.3%), neoplastic (15%), inflammatory (4.1%) and other lesions (14.2%). Grossly, hyperplasia was characterized by a variable amount of whitish nodules, ranging from 0.2-1.5 cm of diameter. In 72.9% of the hyperplasia cases, the nodules were composed by cells of the glomerulosa zone. Most of the animals that showed hyperplastic lesions consisted of females (60.4%), elderly (46.9%) and purebred dogs (55.6%). Fatty degeneration was the most prevalent degenerative lesions (54.7%), characterized by cells of the fasciculata and reticularis zones with large cytoplasmic vacuoles. Among the neoplastic changes, primary tumors were the most prevalent (75.7%), with predominance of adenomas (57.1%), followed by pheochromocytomas (25%) and cortical carcinomas (17.9%). Metastatic tumors corresponded to 24.3% of all cases of neoplastic changes. The adrenal glands were the site of metastasis of mammary gland carcinoma, osteosarcoma, melanoma, lymphoma, cholangiocarcinoma, histiocytic sarcoma and lung adenocarcinoma. Under “other lesions”, adrenal of stress was the most prevalent change (37.1%). It was characterized histologically by a cortex with irregular appearance, with areas of mild cell vacuolation in the fasciculata zone, interspersed with hypereosinophilic cell groups. This study allowed the conclusion that the lesions in adrenal glands of dogs are extremely common, highlighting the importance of a careful evaluation of this organ in the routine of pathological diagnostic.
Diseases of dogs; endocrine system; adrenal glands