Granular-cell myoblastoma of the cercum: report of a case.

A 9-mm granular-cell myoblastoma of the cecum found incidentally during appendectomy in a 17-year-old-girl is reported. Electronmicroscopic findings favor origin of the granular cells from an undifferentiated mesenchymal (fibroblast-like) cell. Review of the small number of previously reported cases revealed three involving the cecum, one each in the ascending and transverse colon and two in the rectum. Four patients were asymptomatic and their lesions were found incidentally. Three lesions simulated maligancy clinically; these patients underwent right hemicolectomy.