개의 결장 간질종양에 대한 영상의학 및 면역조직화학 진단 1예

Medical imaging and immunohistochemical diagnosis of gastrointestinal stromal tumor originated from colon in a dog

Gastrointestinal stromal tumor (GIST) is one of the mesenchymal tumors originated from gastrointestinal submucosa. A 10 year-old, male, mixed breed dog with persistent diarrhea, anorexia and lethargy was referred to Haemaru Animal Referral Hospital. Large mass originated from the transverse colon was observed and large amount of ascites and free gas were found on abdominal radiography and ultrasonography. The ascites was septic exudate mixed with bacteria that consisted with intestinal perforation. There was no metastatic lesion. This mass was tentatively diagnosed as adenocarcinoma, leiomyosarcoma (LMS) and lymphosarcoma and surgical resection and histilogical examination were planned. However, according to owner's request, the patient was euthanized and then the necropsy was performed. About 10 cm sized mass originated from the cecum, ascending colon and transverse colon was adhered to surrounding mesentery and the perforation and large amount of ascites were observed. GIST was suspected on histopathologic examination and confirmed according to CD 117 expression in immunohistochemistry. GIST, derived from interstitial cells of Cajal, can be distinguished from LMS and leiomyoma (LM) on the basis of expression of CD117 (KIT) immunohistochemically. GIST has a different biological behavior and clinical course compared with LMS and LM, therefore definite diagnosis for GIST using immunohistochemistry is clinically important to predict the precise prognosis of the patient.