Oral granular cell tumours: a histological and immunocytochemical study.

In a series of nine cases of intra-oral granular cell tumors (GCTs) an attempt was made, using both histochemical and immunocytochemical methods, to determine whether these tumours show Schwann-cell or neuroendocrine differentiation. Positive immunostaining with protein gene product 9.5 (PGP 9.5), neurone-specific enolase (NSE) and S-100, in contrast to predominantly negative immunostaining in 12 cases of neurilemmoma of the head and neck, and a similar pattern of staining with luxol fast blue to five known neuroendocrine tumours, strongly suggests that granular cell tumors may be neuroendocrine in nature.