Salivary duct carcinoma of the parotid gland: report of a rare case with a comparative study of aspiration cytology and histomorphology.

Background: Salivary duct carcinomas affecting primarily the parotid gland are extremely rare (0.2-2% of all salivary gland tumors). These carcinomas are considered to be of high grade malignancy, with mortality in up to 70% of cases.