Immunohistochemical Demonstration of EMA/Glut1-Positive Perineurial Cells and CD34-Positive Fibroblastic Cells in Peripheral Nerve Sheath Tumors

Expression of S-100, EMA, CD34 and presence of mast cells in eight oral neurofibromas, and a review of 127 cases of the literature

“…In our series, none of the cases exhibited spindle cells whose nuclei or cytoplasm stained positive for EMA. This marker is expressed in perineural cells, and normal nerves are characterized by EMA-positive cells and S-100 protein-negative cells (15) . Despite the existence, as demonstrated by ultrastructural studies, of perineural-like cells in neurofibromas, immunohistochemical studies using EMA as a marker for these cells have produced variable expression (15,25,38) .…”

“…This marker is expressed in perineural cells, and normal nerves are characterized by EMA-positive cells and S-100 protein-negative cells (15) . Despite the existence, as demonstrated by ultrastructural studies, of perineural-like cells in neurofibromas, immunohistochemical studies using EMA as a marker for these cells have produced variable expression (15,25,38) . The CD34 antigen, expressed by hematopoietic progenitor cells of myeloid and lymphoid lineages, has also been recently identified in peripheral nerve sheath tumors (21) .…”

“…S-100 protein is found predominantly, but not exclusively, in the nervous system. This protein is expressed by Schwann cells (5) and is very useful for the identification of tumors composed of these cells (15) . Neurofibromas present a variable number of S-100 positive cells that may localize to different areas of the same tumor (5) , corroborating our findings of the variable extent of staining (diffuse or focal) for these cells.…”

“…Ultrastructurally, neurofibromas exhibit significant heterogeneity, largely due to the involvement of a variety of cellular constituents: Schwann cells, perineural-like cells, endoneurial fibroblasts, intermediate cells, and mast cells (15,35) . Immunohistochemistry (IHC) has been instrumental in confirming this heterogeneity and represents an auxiliary method in the diagnosis and identification of this neural tumor (6,15,29) .…”

“…Immunohistochemistry (IHC) has been instrumental in confirming this heterogeneity and represents an auxiliary method in the diagnosis and identification of this neural tumor (6,15,29) . The S-100 protein marker has been widely used in the identification of Schwann cells and is important for the diagnosis of neural sheath tumors (30) .…”