Follicular Dendritic Cell Sarcoma
Follicular Dendritic Cell Sarcoma (FDCS) is composed of spindle, oval, or epithelioid cells arranged in fascicular, storiform, whorled, or diffuse growth patterns. The tumor cells are admixed with small lymphocytes and plasma cells. Variations in the histologic appearance include: perivascular spaces filled with proteinaceous fluid and lymphocytes (shown here) resembling thymoma or thymic carcinoma; lobulated growth pattern with prominent fibrous septa surrounding individual tumor nodules. Tumors resected after chemotherapy or radiation therapy show squamous metaplasia, foamy histiocytes, and increased pleomorphism.