Granular cell lesions of the jaws and oral cavity: a clinicopathologic, immunohistochemical, and ultrastructural study.

A clinicopathological, immunohistochemical, and ultrastructural study of 44 oral granular cell lesions was performed. A total of 35 mucosal granular cell tumors, 4 granular cell ameloblastomas, 1 lichen planus with granular cell change, and 3 congenital epulides of the newborn were studied. Pseudoepitheliomatous hyperplasia was found to occur in only a minority of these cases. Immunohistochemically, the majority of granular cell lesions were uniformly positive for S-100 protein and focally positive for vimentin in one half of the cases, suggestive of origin from a Schwann cell or a precursor mesenchymal cell. Congenital epulis of the newborn and central odontogenic granular cell tumor were negative for S-100 protein, epithelial membrane antigen (EMA), and prekeratin, suggesting a mesenchymal origin for these lesions.