title: Immunohistochemical characterization of palisaded, encapsulated neuroma.
abstract: Eleven cases of palisaded, encapsulated neuroma (PEN) were studied by routine light microscopic and immunohistochemical methods. PEN showed the following staining reactions: strong, diffuse for S-100 protein (11/11) and collagen Type IV (Col. IV) (11/11); moderately strong, focal for myelin basic protein (MBP) (9/11) and Leu-7 (9/11); weak, focal for MBP (2/11), Leu-7 (2/11), neuron specific enolase (NSE) (4/11), neural filaments (NF) (5/11), epithelial membrane antigen (EMA) (6/11), and negative for glial fibrillary acidic protein (GFAP). Bielschowsky silver stain was positive in 11/11, but only four cases contained numerous axons. Col. IV and EMA stains showed a complete capsule in 1/11, incomplete capsules in 5/11 and no discernible capsules in the remainder. We concluded that (1) the immunologic profile of PEN is not specific; (2) conventional silver stain remains a suitable method to demonstrate axon-like structures; (3) the ratio of axons to Schwann cells is variable and generally less than 1:1, as previously assumed; (4) MBP and Leu-7 coexpression in Schwann cells suggests myelinization of some of the nerve fibers; (5) the pattern of EMA reaction supports perineurial cell involvement in PEN; and (6) despite the current definition of PEN, they are usually not completely encapsulated as evidenced by Col. IV and EMA strains.
authors.affiliation: Department of Pathology, University of Iowa, Iowa City.
authors.forename: Z B
authors.initials: ZB
authors.lastname: Argenyi
mesh_terms: D000943:Antigens, Differentiation / Q000032:analysis; D000951:Antigens, Neoplasm / Q000032:analysis*; D018959:CD57 Antigens; D003094:Collagen / Q000032:analysis; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007382:Intermediate Filaments / Q000276:immunology / Q000473:pathology; D008562:Membrane Glycoproteins / Q000032:analysis; D018396:Mucin-1; D004676:Myelin Basic Protein / Q000032:analysis; D009463:Neuroma / Q000737:chemistry / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D009418:S100 Proteins / Q000032:analysis; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology*
chemical_list: D000943:Antigens, Differentiation; D000951:Antigens, Neoplasm; D018959:CD57 Antigens; D005904:Glial Fibrillary Acidic Protein; D008562:Membrane Glycoproteins; D018396:Mucin-1; D004676:Myelin Basic Protein; D009418:S100 Proteins; D003094:Collagen; D010751:Phosphopyruvate Hydratase