Synchronous tumors arising in a single major salivary gland.

Multiple separate tumors arising in the major salivary glands are distinctly unusual. The records on 25 patients with synchronous unilateral salivary gland tumors on file at St Louis University and at the Armed literature. Bilateral tumors arose more frequently than multiple unilateral ones. The most common tumors with bilateral synchronous or metachronous development are the Warthin tumors, with more than 100 reported cases; the mixed tumor with at least 34 cases; and the acinic cell carcinoma, with 12 reported cases. The Warthin tumor also was the most likely to present with multifocal unilateral involvement with 29 tumors having three or more separate foci of tumor. The next most common tumor combinations are a Warthin tumor and a mixed tumor (20 cases), the multifocal membranous basal cell adenoma (12 cases), and multiple oncocytomas (nine cases). Numerous other tumor combinations were found covering the range of salivary gland neoplasia, however one of the tumors usually was a mixed tumor or a Warthin tumor.