Central granular cell tumor of the jaw. An electron microscopic and immunohistochemical study.

Central granular cell tumor of the jaw was formerly known as granular cell ameloblastic fibroma; recently, the term central granular cell odontogenic fibroma has been proposed. This study attempts to determine the ultrastructural features and selected immunohistochemical properties of the tumor cells. Four formalin-fixed specimens were processed for electron microscopy, and for immunohistochemical staining with antiactin, anti-glial fibrillary acidic protein, and OKT6 (CD1) with the avidin-biotin-peroxidase complex method. Tumor cells contained many primary lysosomes, autophagic vacuoles, and phagocytic vacuoles. The phagocytic vacuoles appeared to contain collagen fibrils. Tumor cells stained positive with antiactin and OKT6 (CD1), and negative with anti-glial fibrillary acidic protein. The results indicate that tumor cells are actively phagocytic and suggest that tumor cells might arise from Langerhans' cells.