Granular cell leiomyoma of the oral cavity.

Granular cytoplasmic change is a reported but uncommon finding in leiomyoma. Leiomyoma in the oral cavity is also uncommon, and granular cell change in oral leiomyomas, to the best of our knowledge, has not been previously reported in the English literature. Two cases of oral leiomyomas with significant granular cell change are presented. These tumors may be confused with the more common granular cell tumor, however, routine histology and immunohistochemistry aided in establishing the diagnosis. Ultrastructural studies were done for one case. Both tumors were immunoreactive for muscle markers, namely, smooth muscle actin and desmin. One of the tumors (case 2) reacted postiviely for HHF-35 and alpha-1 antitrypsin. The tumors were unreactive for S-100 protein, pancytokeratin, myoglobin, and factor VIII related antigen (case 2).