Clinical manifestations of recurrent parotid pleomorphic adenoma

Abstract

Objectives: This study was undertaken to confirm the clinical characteristics of recurrent pleomorphic adenoma (RPA), and to identify those factors that affect the development of malignant transformation (MT) from RPA. Methods: The medical records of 270 patients, who were operated upon for parotid PA, were retrospectively reviewed. The pathologic specimens of a selected series of 23 patients were reviewed for histologic subtype and microscopic multi-nodularity. Results: Mean age of initial operation in RPA without MT (RPA-MT) group was significantly lower than that of primary PA group. Mean age of the revision operation in RPA with MT (RPA+MT) group was significantly greater than that of RPA-MT group. Mean interval from operation to recurrence shortened after each revision operation. The risk of MT and additional recurrence increased significantly with recurrence. In RPA-MT group tumor recurrence occurred in 21.4% of patients despite a clear resection margin. Conclusion: The risk factors for MT may be an age of over 45 yr and multiple recurrences. However, younger patients are more at risk of recurrence. A clear resection margin cannot guarantee a cure in RPA, and it seems that parotid pleomorphic adenomas slowly gain malignant characteristics after repeated recurrences. © 2009 Korean Society of Otorhinolaryngology-Head and Neck Surgery.