[Basal cell adenomas of the salivary glands. Analysis of 7 cases and review of the literature. Comparative study with cylindromas].

Basal cell adenomas, of which 7 cases are reported here together with 63 others collected in the literature, are benign tumours of the salivary glands, preferentially localised in the parotid and in the upper lip. Mobile, non-ulcerated and painless, these nodules with an average diameter of 2 cm are well circumscribed, fleshy or cystic. Their morphology is characterised by the proliferation of uniform, small cells, with scarcely visible cytoplasm, arranged in layers, cords and canals, which may be ectasic or cystic. Peripheral elements, individualising these different structures, are arranged in palissades and are regularly surrounded by a basal membrane. The histological analogies between basal cell adenomas and cylindromas merely reflect their ultrastructural similarities, cellular as well as architectural. These two neoplasms may be distinguished on the basis of two essential morphological criteria:--basal cell adenomas are well circumscribed, whilst cylindromas are invasive;--the cells in adenomas are closely juxtaposed, endowing the various structures of these tumours with a dense appearance, whilst cylindroma cells are generally separated by clear spaces corresponding to extreme development of the intercellular spaces.