Mucoepidermoid carcinoma of the transverse colon: A rare tumor entity with literature review.

Mucoepidermoid carcinoma of the gastrointestinal tract is a rare entity. Here, we report a case of mucoepidermoid carcinoma of the transverse colon in a 77-year-old woman who presented with a 2-month history of epigastrium pain, diarrhea and melena. A giant tumor with apparently invading gallbladder was found by enhanced CT scan, then the extended resection of transverse colon was performed for the patient 2 weeks later. Microscopically, the tumor was composed of solid nests of epidermoid and Periodic Acid-Schiff (PAS)-positive mucin-producing cells with desmoplastic stroma. The epidermoid component of the tumor contained intercellular bridges and individual cell keratinization. Thus, the case was diagnosed as mucoepidermoid carcinoma of the transverse colon. Unfortunately, despite chemotherapy, the patient developed systemic failure and died 7 months postoperatively.