Collision epithelial and stromal tumours of the stomach: a case report.

Collision epithelial and stromal tumours of the stomach are uncommon, and only a few cases have been reported in the literature. We describe a new case of a 54-year-old man who presented with bloody emesis. An oesophagogastroduodenoscopy revealed a stomach induration, and preoperative histological diagnosis was signet ring carcinoma. Total gastrectomy was performed and histological examination revealed a gastric collision tumour composed of gastrointestinal stromal tumour intermixed with a primary signet ring carcinoma. The neoplastic cells of the gastrointestinal stromal tumour were diffusely positive for CD117, while the signet ring cells were positive for cytokeratin. There was no transition between the two components.