Peripheral ameloblastoma: a study of 21 cases, including 5 reported as basal cell carcinoma of the gingiva.

The peripheral ameloblastoma and the basal cell carcinoma of the gingiva are probably the same lesion. This article describes the clinical features, natural history, and histopathology of nine acceptable cases published as peripheral ameloblastoma, five lesions published as basal cell carcinoma of the gingiva, and seven unpublished cases of peripheral ameloblastoma. Tissue sections were studied from seven of the cases published as peripheral ameloblastoma, three of the cases published as basal carcinoma, and all the unpublished cases. The peripheral ameloblastoma may exhibit several of the various histologic patterns found in the intraosseous ameloblastoma but has a marked tendency to be acanthomatous. These lesions appear to arise from either remnants of the dental lamina within the gingiva or from the surface epithelium. They are relatively innocuous lesions lacking the persistent invasiveness of intraosseous ameloblastoma. Peripheral ameloblastomas should be excised with a small margin of normal tissue and the surgical site re-examined periodically.