title: Ultrastructural study of a perineurioma.
abstract: A case of soft tissue tumor in the left brachialis muscle of a 49-year-old Japanese female patient was studied by electron microscopy. The tumor was diagnosed as intramuscular myxoma by light microscopy, but electron microscopic observation revealed that the tumor almost entirely consisted of cells similar to normal perineurial cells. The tumor cells possessed long, slender cytoplasmic processes covered by well-developed but discontinuous basal laminae, clusters of pinocytotic vesicles, and infrequent intercellular junctions. Perineurial cells have also been observed in other peripheral nerve lesions: neurofibromas, nerve sheath myxomas, and localized hypertrophic neuropathies. However, the term "perineurioma" or "perineurial cell tumor" should be reserved for discrete tumorous masses that are almost entirely composed of perineurial cells without evidence of residual axons, Schwann cells, fibroblasts, or tactile corpusclelike structures. Perineurioma may represent a third category of peripheral nerve sheath tumors, ultrastructurally distinct from schwannomas and neurofibromas.
authors.affiliation: Department of Orthopaedic Surgery, Teikyo University School of Medicine, Ichihara Hospital, Chiba Prefecture, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohno
authors.forename: P
authors.initials: P
authors.lastname: Park
authors.forename: M
authors.initials: M
authors.lastname: Akai
authors.forename: S
authors.initials: S
authors.lastname: Kamura
authors.forename: K
authors.initials: K
authors.lastname: Murase
authors.forename: H
authors.initials: H
authors.lastname: Kimura
authors.forename: H
authors.initials: H
authors.lastname: Kadoya
authors.forename: S
authors.initials: S
authors.lastname: Manabe
authors.forename: K
authors.initials: K
authors.lastname: Nagao
authors.forename: I
authors.initials: I
authors.lastname: Sugano
mesh_terms: D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D008875:Middle Aged; D009442:Neurilemmoma / Q000145:classification / Q000648:ultrastructure*; D009455:Neurofibroma / Q000145:classification / Q000648:ultrastructure*; D010524:Peripheral Nervous System Neoplasms / Q000145:classification / Q000201:enzymology / Q000648:ultrastructure*; D010751:Phosphopyruvate Hydratase / Q000032:analysis
chemical_list: D010751:Phosphopyruvate Hydratase