Adenoid cystic carcinoma of the salivary glands: an immunohistochemical study.

Twenty-four cases of adenoid cystic carcinoma from the Salivary Gland Registry of the University of Hamburg were analysed with respect to their differentiation and subclassification. With immunohistochemical methods, several groups of marker substances were analysed in these tumors: marker for a glandular function; immunoglobulins; metalloproteins; tumor markers; substances associated with the basal membrane and carbohydrate chains. The following patterns of histological differentiation were found: cribriform pattern with typical pseudocysts; tubular pattern with ductal elements; trabecular pattern with predominance of hyalinized stromal elements; basaloid pattern with low differentiated cells. For every pattern, a special immunohistochemical profile could be established. The morphological and immunohistochemical analysis revealed the following relation between the different patterns: Origin of the malignant proliferation is presumably the terminal ductal system of the salivary glands (indifferent cell of the reserve cell type). This cell can differentiate in 2 directions: a myoepithelial and a ductal cell type. Immunohistochemically, the presence of basement membrane-associated substances is accompanied by the appearance of myoepithelial-like cells. The presence of secretory products is a feature of ductal cells.