Expression of Glut-1 and Claudin-1 in Follicular Dendritic Cell Sarcoma

To the Editor: Follicular dendritic cell (FDC) sarcoma is a rare neoplasm of FDCs that affects predominantly lymph nodes, with occasional extranodal involvement. The diagnosis of FDC sarcoma depends on the recognition of the typical morphologic features and the characteristic immunophenotype, that is the expression of CD21 (C3d receptor) and CD35 (C3b receptor). Other FDC markers include CD23, R4/23, KiM4, KiM4p, and Ki FDC lp. In addition FDC sarcomas may express vimentin, fascin, CD68 (Kp-1), CD4, CD19, CD45, CNA.42, desmoplakin (desmosomeassociated protein), and EMA. Occasionally, weak expression of S-100 protein, myosin, and actin may be encountered. There are no reports of Glut-1 or Claudin-1 expression in this type of sarcomas. We studied 5 cases of FDS sarcoma, (3 nodal and 2 extranodal) all of which presented typical histology and were positive for CD35, CD21, and CD23, indicating the FDC origin. © Applied Immunohistochemistry & Molecular Morphology