Benign Pleomorphic Adenoma of Parotid Gland with Unusual Course and Histological Findings; Report of Two Cases.

Two female patients aged 37 and 46-years visited our out-patient clinic complaining of a tumor of the right parotid gland. A few weeks after the first visit, the tumors had become smaller. X-ray CT examinations of each patient showed a ring-shaped mass enhanced by the contrast medium in the lateral lobe of the parotid gland. The clinical course and the results of examinations led to a diagnosis of lymphadenitis or inflammatory cystic lesion. Both tumors were surgically extirpated, and histological examination showed benign pleomorphic adenoma with a wide area of central necrosis. The cause of the central necrosis is unknown. This type of benign pleomorphic adenoma is very rare but calls our attention to its possibility and the importance of accurate diagnosis and appropriate therapy.