[Oncocyte cells in salivary tumors: frequency, histoenzymological and ultrastructural characteristics]

Two types of salivary monomorphic adenomas, the so-called adenolymphoma and oncocytoma (75 cases in a series of 873 salivary gland tumors) were studied. These tumors were almost always located in major salivary glands (essentially in the parotid gland). They were much more common in men (85%) than in women. The oncocyte represented the characteristic cell in these two neoplasms. By electron microscopy, they were seen to contain numerous and abnormal mitochondriae and well-developed lysosomal systems. These findings were correlated with a high level of activity of oxidative enzymes and of acid phosphatases. The histogenesis of these tumors was discussed. They seemed to arise from aberrant striated ducts embedded in heterotopic lymph nodes. The tumoral oncocytes would suffer a primary disturbance of their oxidative metabolism followed by a compensative mitochondrial hypertrophy.