BASAL-CELL ADENOCARCINOMA OF MINOR SALIVARY AND SEROMUCOUS GLANDS OF THE HEAD AND NECK REGION

Basal cell adenocarcinoma of salivary glands is an uncommon and recent ly described entity occurring almost exclusively at the major salivary glands. This report provides an overview of the clinicopathologic pro file of this neoplasm by including the personal experience on the clin ical features, microscopic and ultrastructural characteristics, prolif eration activity, and DNA tumor patterns of 12 lesions occurring at th e minor salivary glands of the head and neck region, where basal cell adenocarcinoma is probably an underecognized entity, previously report ed under different designations. Basal cell adenocarcinoma predominate s at the seventh decade without sex preference. The tumors affecting t he minor salivary glands occur most frequently at the oral cavity (jug al mucosa, palate) and the upper respiratory tract. The prevalent hist ologic tumor pattern is represented by solid neoplastic aggregates wit h a peripheral cell palisading arrangement frequently delineated by ba sement membrane-like material. The neoplastic clusters are formed by t wo cell populations: the small dark cell type (that predominates) and a large cell type. Necrosis, either of the comedo or the apoptotic typ e, is a frequent finding. Perineural growth occurs in 50% of the cases and vascular permeation in 25%. Immunohistochemistry identifies a dua l differentiation with a reactivity pattern indicative of ductal epith elial and myoepithelial differentiation, which can be confirmed by ele ctron microscopy. The differential diagnosis of the neoplasm includes its benign counterpart, the basal cell adenoma, solid variant of adeno id cystic carcinoma, undifferentiated carcinoma, and basaloid squamous carcinoma. The tumors recur more frequently than lesions originating in major salivary glands. Mortality is associated with the anatomic si te of the lesion, advanced stage, residual neoplasia at surgery, and t umor recurrence. The importance of recognizing basal cell adenocarcino ma outside major salivary glands is related to the clinical behavior o f the neoplasm that seems to be less indolent than that of tumors aris ing in major salivary glands. Copyright (C) 1996 by W.B. Saunders Comp any.