Gastrointestinal stromal tumor (GIST) in a female Terrier dog

Abstract

This case report describes two intestinal masses compatible with gastrointestinal stromal tumor (GIST) in a nine-year-old female Terrier dog. The dog presented with complaints of anorexia and vomiting following the ingestion of food. Abdominal ultrasonography revealed two masses in the ventral aspect of the stomach and duodenum. The masses were 6.1x3.7x2.3 cm and 3.2x2x1.7 cm in size, and the cut surfaces of the masses were grayish-white-yellow and had a solid appearance. The greater mass invaded the intestinal serosa and mucosa. Cut surfaces were grayish white- yellow and had a solid appearance. Following routine histopathological processing, masses were sectioned at four mu m, stained with Hematoxyline&Eosine (H&E), and immunohistochemically with anti-c-KIT (CD117) antibody. Microscopically, the tumor comprised cells with an oval vesicular nucleus, spindle-shaped eosinophilic cytoplasm, and a prominent nucleolus. Mitotic activity increased significantly (5-6 mitoses at x400 magnification). Binucleated cells were observed. Large necrotic areas surrounded by inflammatory cells were noticed. The gastrointestinal stromal tumor is a neoplasm originating from intestinal Cajal cells, and the tumor is mainly confused with leiomyoma and leiomyosarcoma; immunohistochemical demonstration of c-KIT is performed for differential diagnosis.