Ultrastructural cytochemistry of phosphatases in the ductal component of pleomorphic adenoma of human parotid and submandibular salivary glands.

Some ductal cells of pleomorphic adenomas showed evidence of secretory activity, with apical secretory granules, thiamine pyrophosphatase activity in the Golgi apparatus, and acid phosphatase activity in GERL-like structures and in immature secretory granules. Alkaline phosphatase activity was demonstrated rarely at the luminal plasma membrane and in intracellular vesicles, suggesting resorptive activity. ATPase reaction product was associated with contiguous surfaces of tumour cells, particularly of those cells adjacent to the basement membrane, these latter cells apparently differentiating in a different manner to the luminal cells. A comparison of luminal ductal cells of the tumours with normal salivary glands revealed most similarity with intercalary ductal cells.