左側耳下腺に同時性にみられた多形性腺腫とＷａｒｔｈｉｎ腫瘍の１例

Abstract

The synchronous occurrence of histologically distinct tumors in the same parotid gland is rare, withonly a frequency of 0.2 % based on a report by Turnbull and Frazell. We report a case of pleomorphic adenomaand Warthin's tumor that occurred simultaneously in the same parotid gland.A 55-year-old man presented with a painless swelling in the left parotid region, present for 9 years. The patientvisited our hospital at this time because of a recent increase in the size of the swelling. The mass in the superiorpart of the parotid gland was elastic hard and clearly demarcated. In contrast, the mass in the lower pole of parotidgland was elastic soft and indistinctly demarcated.We evaluated the tumors by 99mTc salivary gland scintigraphy, 67Ga scintigraphy, ultrasonography, parotidsialography, and computed tomographic scanning. We also performed an aspiration biopsy of the tumor in thelower pole of the parotid gland to make a preoperative diagnosis. The tumor in the lower pole of the parotid glandwas strongly suspected to be a Warthin's tumor, while the tumor in the superior part was considered to most likelybe a benign tumor. These tumors were resected by a superficial parotidectomy. As for the histopathologicaldiagnosis, the tumor from the lower pole was confirmed to be a Warthin's tumor, while the tumor in superior partturned out to be a pleomorphic adenoma.