Extranodal follicular dendritic cell sarcoma of the palate

Follicular dendritic cell tumors are uncommon and usually occur in lymph no des. We report the case of a follicular dendritic cell tumor that occurred in the palate of a 14-year-old boy and manifested itself as a nodular mass. Histologically, the neoplasm consisted of spindle-shaped or oval-shaped ce lls with eosinophilic cytoplasms and nuclei with delicate, dispersed chroma tin. The lesional cells were principally arranged in diffuse, fascicular pa tterns with vaguely whorled or storiform areas. Focal multinucleate tumor g iant cells and lymphocytes were observed throughout the neoplasm. Immunohis tochemically, tumor cells were positive for the follicular dendritic cell m arkers CD21, CD35, and CD23 and for S-100 protein, CD68, and muscle-specifi c actin. Tumor cells were negative for LCA, CD20, EMA, CK (AE1/AE3), HMB45, and CD34. Lymphocytes were positive for LCA and CD45RO. Although follicula r dendritic cell sarcoma is a very uncommon tumor, it should be included in the differential diagnosis of tumors in this location.