Gingival granular cell tumor of the newborn (congenital "epulis"): ultrastructural observations relating to histogenesis.

The authors report the electron microscopic features of gingival granular cell tumors (GGCT) resected from two newborn girls. Although origin from odontogenic epithelium has been proposed, the ultrastructural findings strongly support histogenesis from stroma (mesenchymal) cells. Tissue assay for estrogen receptors was negative, but considering the marked predilection of GGCT for females, a hormonal factor (or factors) may still be important in the development of GGCT. Clinical and morphologic features distinguishing GGCT from granular cell "myoblastomas" are briefly emphasized.