A case of leiomyosarcoma of the small bowel mesenterium.

Leiomyosarcoma of the small bowel mesenterium is a rare entity. Approximately 21 cases originating from the small bowel mesenterium have been described in the Japanese literature. Differentiation from its benign counterpart, leiomyoma, and other connective tissue tumors is often difficult, but it is important because each respective tumor type has an entirely different prognosis. The case of a 65 year-old-man in whom an 9 x 6 x 5 cm leiomyosarcoma of the mesenterium was excised surgically is presented.