[Complicated sigmoid tumor: perforated amebiasis].

Amoeboma is an inflammatory mass of the colon. It can be an inaugural symptom and thus pose the problem of differential diagnosis with colon cancer. The purpose of this report is to describe the case of a 43-year-old patient who presented with acute abdomen. Physical examination revealed a perforated circumferential mass in the sigmoid colon. Based on a presumptive diagnosis of colonic cancer complicated by perforation, segmental colectomy was performed. Histological examination of the surgical specimen demonstrated colonic amoeboma. The patient was treated using metronidazole. Although rare, amoeboma must be considered in differential diagnosis of cancer of any colonic mass.