Fine needle aspiration cytology of follicular dendritic cell sarcoma : A case report

Follicular dendritic cell (FDC) sarcoma is a rare, recently described neoplasm that shows differentiation similar to that of follicular dendritic cells. It must be differentiated from metastatic neoplasms and other rare, nonlymphoid nodal lesions. A 76-year-old man underwent fine needle aspiration of a recurrent laterocervical mass. Sixteen months earlier, the original tumor was excised and proved to be an FDC sarcoma. Smears exhibited a dual cell population composed of large cells with abundant cytoplasm and a lymphoid component that consisted mainly of lymphocytes and plasma cells. Large cells were atypical and distributed in ill-defined groups and as single cells. Nuclei were round to oval and pleomorphic, with irregular contours and nucleoli. Binucleation and multinucleation were occasionally seen. After the cytologic diagnosis, the tumor was excised and showed typical histologic and immunophenotypic features of FDC sarcoma. The morphologic features of FDC sarcoma seem characteristic enough to permit its preoperative recognition. Its cytologic definition increases our knowledge of rare, nonlymphoid, primary nodal tumors, allowing better differentiation from metastatic neoplasms.