Gastrointestinal stromal tumor of the gastric serosa protruding to the greater omentum. Report of a giant tumor with a rare histological pattern.

Abstract

We report an unusual case of a 76 year old woman admitted to our hospital for investigation of anemia and palpable epigastric mass. Intraoperatively a huge (19 cm), well defined tumor was found adhering to the stomach wall, protruding into the greater omentum and compressing the transverse colon. A tumorectomy was performed and the greater omentum was removed due to its close relation. Pathology revealed a high risk Gastrointestinal Stromal tumor of the gastric serosa. Histologically the tumor was of mixed type (spindle and epithelioid cells) with hem-angio-peri-cytomatoid pattern peripherally, variably myxoid stroma, central necrosis and cytologic pleomorphism. On immunohistochemical examination there was a consistent positivity for c-kit (CD-117) and CD-34, but without myogenic or neural differentiation. We consider this case unusual because of its huge size, its gastric serosal location and its extremely rare histological pattern.