Unicystic mucoepidermoid carcinoma presenting as a salivary duct cyst.

A cystic swelling in the parotid gland should lead to a differential diagnosis that includes benign cystic lesion of the gland, benign tumors that are frequently associated with cystic degeneration or entirely cystic de novo, or even a malignant neoplasm. The case presented is that of a cystic parotid swelling of 2 years' duration in a 52-year-old female patient. The clinical differentials in the present case were reviewed and were entirely different from the final histological diagnosis of low-grade mucoepidermoid carcinoma. The uniqueness of this case is the very rare unicystic presentation of the lesion. The authors also discuss why the clinical and radiological investigations were not suggestive of the final diagnosis.