[Secondary malignant tumors of the parotid]

Secondary malignant tumors of the parotid gland are uncommon. They arise from primary tumors located in the head and neck or from distant primary tumors. The formers are dominated by squamous cell carcinomas and melanomas, the latters by renal and lung cancers. Distinction between malignant primary tumors and metastasis of other primary tumors to the parotid gland is very important to appreciate, because the result of this will change therapeutic procedure and the evaluation of prognosis.

A series of 23 patients with tumors metastatic to the parotid gland are reported. All clinical and pathological data were reviewed. The management of secondary tumors of the parotid gland and the results were analyzed in order to try to identify common features and implications for management.

The most frequent histologic types were squamous cell carcinoma and melanoma. Most primary tumors occurred in the head and neck. Metastasis to the parotid gland presented with a median time of 18 months after diagnosis of the primary tumor. All the patients had a parotid mass. No patient had facial nerve weakness. Parotid metastases were treated by superficial parotidectomy with preservation of the facial nerve in all cases, associated in 14 cases with a homolateral selective neck dissection and in 6 cases with a homolateral radical neck dissection. Twenty-one patients were submitted to radiation therapy. Seven patients died after the treatment: in 3 cases, death was due to a local recurrence with cervical relapse; 4 patients presented cervical and metastatic lesions.

This retrospective review confirmed that patients with involvement of cervical nodes and metastatic parotid tumors have a worse prognosis than those without involvement of cervical nodes. The addition of postoperative radiotherapy provides no additional benefit.