[Various aspects of the morphology of granular cell tumors]

Histology and ultrastructure of human granular cell tumors (GCT) are studied. Apart from "granular" cells which are the main component of the tumor, GCT contain the cells of ordinary structure with signs of neurogenic differentiation, cell processus typical for the nervous tissue and peripheral nervous tissue tumors (these processus are in a close space connection with "granular" cells) as well as structurally transitional cells. This implies that "granular" cells are likely to originate from the ordinary lemmocytes as a result of disturbance and hypertrophy of intracellular processus. Preoperative diagnosis of this rare peculiar neurogenic tumor is difficult and the diagnosis is possible only after the operative material examination. If other signs of malignancy are lacking, infiltrative growth typical for these tumors allows one to consider them locally-destructive neoplasms.