Follicular dendritic cell tumor in the oro-pharyngeal region: report of a case and a review of the literature.

A case of follicular dendritic cell tumor (FDC tumor) arised in the aro-pharyngeal region is reported in a 16-year-old Japanese boy. He had a swelling in the right retromolar trigone and soft palate. Clinical examination disclosed a 25 mm x 30 mm, elastic hard, ulcerated mass. CT scans showed a low density lesion in the right medial parapharyngeal area. The biopsy specimen revealed a low-grade malignant tumor. The patient underwent a tumorectomy which was extended to include the adjacent palatine tonsil. The tumor cells, with a clear cytoplasm and oval nucleus, were immunoreactive for S-100 (N/A), CD 21 (1F8), fascin (55K-2) and FDC (CNA42). The fascicular sheet pattern arrangement of the tumor cells was partly characteristic. The final diagnosis was an follicular dendritic cell tumor. Three courses of adjuvant chemoradiotherapy were administered postoperatively. Clinical features, pathological diagnosis and immunohistochemical markers for distinguishing FDC tumor are reviewed.