Follicular dendritic cells and related sarcoma.

Follicular dendritic cells are mesenchymal-derived dendritic cells located in the B follicles, where they capture, retain and present antigens to surrounding B cells, thus playing a pivotal role in triggering and maintaining B-cell adaptive immune response. The term follicular dendritic cells (FDC) was originally introduced by Steinman et al. in 1978. In 1986, Monda and Rosai first reported tumoral proliferations derived from FDC occurring in lymph nodes and the term FDC sarcoma was subsequently coined to identify this neoplasm. FDC sarcoma is nowadays a well recognized entity known to involve both nodal and extranodal sites. In this review we summarize data on physiological functions of FDC in the immune response, their involvement in pathological conditions, and the clinical, histopathological and phenotypic features of FDC sarcoma.