Parotid gland metastases of distant primary tumours: A diagnostic challenge

Metastatic disease is common among parotid malignancies. The majority of primary tumours are located in the head and neck, but primary tumours below the clavicle must also be considered, especially in histological types not usually found in primary parotid or skin tumours.

We performed 644 consecutive parotidectomies between 1980 and 2012. Benign tumours were found in 555 patients (86%) and malignant tumours in 89 patients (14%).

Of 89 malignant tumours, 39 were metastases (44%). In 5 cases, the primary tumour was located below the clavicle (6% of malignant tumours). A carcinoma of the bronchus was subsequently diagnosed in three patients: one patient had breast carcinoma and one renal cell carcinoma.

The majority of metastases in the parotid gland arise from primary tumours of the head and neck. In 10-20% of metastases, the primary tumour arises below the clavicle. Parotid metastases can be the first clinical manifestation of a malignant tumour, and can also occur years after curative intent treatment. Histopathology and immunohistochemistry will offer clues to a possible metastatic process and to primary tumour location. Parotidectomy with complete excision of the tumour can be a curative measure or form an essential part of symptom control and should be considered in all but the most moribund patients.