Multiple synchronous and metachronous neoplasms of the parotid gland: the Chichester experience.

Parotid neoplasms are usually solitary and multiple tumours occurring in an individual are uncommon. The incidence and implications of multiple synchronous and metachronous tumours remains relatively unknown. We reviewed the case notes of 606 patients who had parotidectomies for neoplastic lesions over a 30 year period and identified 30 patients (5%) with multiple primary tumours. There were 24 patients with synchronous tumours and 6 with metachronous tumours. Sixteen of the synchronous tumours (67%) were ipsilateral, whereas all six metachronous tumours were contralateral. Preoperative examination was effective at detecting bilateral tumours but poor at detecting multiple ipsilateral tumours. Multiple tumours were likely to be of the same histology (n=24, 80%) and Warthin's was by far the most common multiple tumour. Ipsilateral tumours of differing histological types and identical tumours other than Wartin's were uncommon. All but one patient had superficial parotidectomies and there were no recurrences.