Ultrastructural and histochemical studies of granular-cell ameloblastoma.

Four cases of granular-cell ameloblastoma were studied by light and electron microscopy, histochemistry and electron enzyme histochemistry. Microscopically, granular cells commonly occurred in a follicular pattern, but, in one case, they were in a plexiform pattern. The high activity of acid phosphatase and electron microscopic features revealed that the cytoplasmic granularity was ascribed to the high content of lysosomes. It was speculated that granular-cell ameloblastoma occurs due to the altered dysfunction of tumor cells, and the age factor is related to the pathogenesis of this tumor.