Follicular Dendritic Cell Sarcoma (FDSC)
Uma Kundu, MD and Muhammad Zulfiqar, MD
Presentation Date: January 2012; Expires: January 2015
A 53 year old male presented with a 6.1 cm, lobulated, well-circumscribed extra-hepatic mass at the level of the porta-hepatis encasing the main portal vein. His initial tumor presented as a peri-gastric soft tissue mass arising in a background of hyaline vascular Castleman disease. At that time, he underwent a partial gastrectomy. The resected neoplasm showed both spindle cells and epithelioid areas. The spindle cells were cytologically low-grade and closely related to foci that resembled hyaline vascular Castleman disease. The spindled areas were positive for CD21, CD35, CXCL13, D2-40, fascin, clusterin and vimentin. A subset of epithelioid cells were positive for CD11c and CD68. In-situ hybridization for Epstein-Barr virus small encoded RNA (EBER) and immunohistochemical markers for T-cells, B-cells, muscle specific antigens, keratin, CD33 and ALK1 were negative. A CT guided FNA biopsy of the recurrent extra-hepatic mass was performed and the images from the aspirate smears and cell block are shown below. The cytomorphologic and immunhistochemical features were similar to the patient's initial peri-gastric tumor.