Follicular dendritic cell sarcoma:: A case report

Background Follicular dendritic cell (FDC) sarcoma is a neoplastic proliferation of spindled to ovoid cells showing morphologic and phenotypic features of follicular dendritic cells. It is a rare tumor that can present in nodal and extranodal sites. Case A 41-year-old woman presented with a 6-week history Of an enlarging lump in her neck. Fine needle aspiration (FNA) was performed. FNA findings led to the diagnosis of malignant tumor. We suggested that it was an FDC sarcoma. The tumor was excised. On microscopic examination, the tumor largely replaced the lymph node. It was composed of oval to spindle cells arranged in sheets and interlacing fascicles with a storiform pattern. The tumor cells showed widespread immunopositivity for CD21. Based on these findings the diagnosis of FDC sarcoma was made. Two years later local recurrence occurred. Conclusion FDC sarcoma has characteristic FNA findings. Once FDC sarcoma is suspected cytologically or histologically, immunohistochemical stains must be performed for reaching the correct diagnosis. Awareness of this rare entity is necessary to avoid its underrecognition.