In view of the morphological similarity between gastrointestinal stromal tumors (GIST) and other sarcomas of the intestine of dogs, the aim was to carry out the histomorphological and immunohistochemical diagnosis of these tumors, associating breed, sex and age, location and tumor invasion. 217 cases were evaluated by histopathology and 36 diagnosed by immunohistochemistry were included (24 GIST and 12 other intestinal sarcomas). Mixed breed dogs were the most diagnosed with GIST, mainly elderly females (9.5±2.2 years); in the other intestinal sarcomas, crossbreeds and Dachshunds, males and females, were equally affected. The cecum was the most affected by GISTs, with tumor invasion of the intestinal layers in all cases. The small intestine was the most affected by the other intestinal sarcomas, with invasion of the layers in most of these tumors. GISTs expressed markers such as CD117 and DOG-1, unlike other intestinal sarcomas. GIST and other intestinal sarcomas denoted histomorphological and immunophenotypic characteristics similar to histopathology, justifying the association of immunohistochemistry for the definitive diagnosis.
Keywords: CD117; DOG-1; GIST; veterinary oncolog
