Metastatic salivary duct carcinoma to the uterus: report of a case diagnosed by cervical smear.

Metastasis to the uterus from extragenital sites is uncommon. We report on a rare case of salivary duct carcinoma (SDC) of the parotid gland with metastasis to the uterus, diagnosed by cervical smear. To the best of our knowledge, this is the first case reported in the literature. A 61-yr-old woman with a prior diagnosis of SDC was admitted to hospital with a fractured left humerus, back pain, and vaginal bleeding. A cervical smear and an endometrial aspiration were performed. The cervical smear showed numerous fragments and many isolated tumor cells in a clean background. The tumor cells were large and had abundant, granular/vacuolated cytoplasm. The nuclei were slightly pleomorphic, with fine chromatin and 1-2 small nucleoli. The malignant cells were morphologically identical to the primary tumor and correlated with the tumor in the endometrial aspiration. A diagnosis of metastatic salivary duct carcinoma was made. Although metastatic SDC to the uterus is rare, this possibility should be considered in the differential diagnosis of a positive cervical smear. This case also illustrates the importance of appropriate clinical history, including the knowledge of a primary tumor which may prevent unnecessary clinical investigations. Diagn. Cytopathol. 1999;21:271-275. Copyright 1999 Wiley-Liss, Inc.