Spindle cell carcinoma of the parotid gland.

Spindle cell carcinomas of the salivary gland are extremely rare, with only a few cases having been previously reported. We present a 55-year-old man with a rapidly enlarging mass in the left parotid gland. Despite radical surgery, the tumour recurred, and led to death 11 months later. Histopathologically, the tumour was composed of two components, a squamous cell carcinoma component and a spindle cell sarcomatoid component. A diagnosis of primary spindle cell carcinoma of the parotid gland was made. Immunohistochemical studies revealed keratin positivity and vimentin negativity in the squamous cell carcinoma component: the spindle cell sarcomatoid component was positive for vimentin and negative for keratin, but showed focal positivity for epithelial membrane antigen. The origin of the sarcomatoid component and the differential diagnosis from malignant mixed tumours are discussed.