Synchronous tumours of the unilateral parotid gland: rare or undetected?

Abstract Introduction: Multiple tumours of the parotid gland with the same histological appearance may occur as synchronous unilateral tumours, but bilaterality has also been reported. Synchronous multiple unilateral parotid tumours with different histology remain rare. Methods: Between January 1988 and May 2002, a total of 341 patients underwent parotidectomy in our department. Medical charts were reviewed retrospectively for synchronous multiple unilateral tumours. Results: Fourteen patients had two or more tumours within the same specimen. The combinations encountered were two to four adenolymphomas ( n =9), adenolymphoma plus pleomorphic adenoma ( n =3), adenolymphoma plus MALT lymphoma ( n =1), and pleomorphic adenoma plus acinic cell carcinoma ( n =1). The outcome was clinical freedom from signs of tumour recurrence in any patient (mean follow-up = 51 months). Conclusion: Synchronous multiple unilateral parotid tumours usually include two or more adenolymphomas and might occur more often than previously realized. The possibility of a concomitant carcinoma, and the prevention of recurrent tumours, may warrant a more radical surgical excision of the parotid gland, accurate intraoperative examination of the resected specimen, and routine histological evaluation of the entire specimen. Preoperative radiological investigation may further increase the chances of finding multiple parotid tumours.