Follicular dendritic cell sarcoma of the parotid gland recurring 6 times within 12 years.

Follicular dendritic cell sarcoma is a rare neoplasm of low to intermediate malignant potential. It can occur in any location where follicular dendritic cells reside, and nearly all the cases reported in clinical notes have occurred as primary lymph node tumors. Carcinosarcoma or true malignant mixed tumor of the salivary gland is a tumor composed of both carcinomatous and sarcomatous elements. It is an exceedingly rare tumor of the salivary glands, and only approximately 60 clinical notes have been reported. In this report, we describe a recurrent carcinosarcoma of the parotid gland that contained an unusual mesenchymal component (follicular dendritic cell sarcoma) in a 42-year-old woman with cytohistologic and immunohistochemical findings. The predominant sarcomatous component made the diagnosis in the current report difficult because only one clinical note on follicular dendritic cell sarcoma in the parotid gland has been previously reported in the English literature. During the 12-year follow-up period, 6 local recurrences were also detected.