An unusual multifocal leiomyosarcoma of the stomach: a light and electron microscopic study.

A multifocal leiomyosarcoma of the stomach originating from the muscularis mucosae with lymph node and distant metastases is described in a 66 year old man. The electron microscopic features of a representative tumor mass and a metastasis confirmed the smooth muscle histogenesis. The light microscopic appearance consistently suggested malignant fibrous histocytoma. The pathological features of gasttric leiomyosarcomas are reviewed with special emphasis on the problem of practical diagnosis. This case also indicates that not all sarcomas with storiform features are necessarily histiocytic in origin.