Multicentric granular cell tumor of the colon: report of a patient with 52 tumors.

Gramular cell myoblastoma is an uncommon benign tumor that can be located anywhere in the body. Multiple tumors of the gastrointestinal tract are quite rare, having been reported infrequently in the English literature. The histologic, immunohistochemical, and electron microscopic findings in our case, as well as in others reported, suggest that its histogenesis may be related to Schwann cells. One case of multifocal granular cell tumor presenting 52 tumors from the cecum to the sigmoid is described, and the previously reported cases with similar presentation are reviewed. We suggest that in such cases, a long period of observation with repeated colonoscopy may be more appropriate than an aggressive approach