title: Soft-tissue perineurioma in a 20-year-old patient with neurofibromatosis type 1 (NF1): report of a case and review of the literature.
abstract: BACKGROUND
  Perineurioma is a rare benign soft-tissue tumor composed of cells showing differentiation toward the perineurial cells of the nerve sheath. Although mutations in the neurofibromatosis 2 (NF2) gene have been documented in this tumor, there is no known association between perineuriomas and type 1 or 2 NF.
  
  
  METHODS
  This is the first report of a case of soft-tissue perineurioma occurring in a patient with NF1.
  
  
  RESULTS
  Histopathologic examination revealed a 2.0-cm well-circumscribed, spindle-cell neoplasm with slender, elongated, bipolar, wavy cytoplasmic processes and wavy, elongated nuclei in a hyalinized stroma with focal myxoid areas. The architecture was composed predominantly of short fascicles with areas exhibiting a storiform pattern. Immunohistochemistry showed positive labeling for epithelial membrane antigen (EMA) but no staining for S-100 and smooth muscle actin (SMA).
  
  
  CONCLUSIONS
  This case illustrates that perineurioma can occur in association with NF1. Perineuriomas can be confused with other spindle-cell neoplasms, and relevant features and immunohistochemistry of these lesions are outlined. The patient has not had a recurrence with limited follow-up.
authors: Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA.
authors: Gregory G
authors: GG
authors: Ausmus
authors: Melissa P
authors: MP
authors: Piliang
authors: Wilma F
authors: WF
authors: Bergfeld
authors: John R
authors: JR
authors: Goldblum
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D006801:Humans; D018396:Mucin-1 / Q000378:metabolism; D018317:Nerve Sheath Neoplasms / Q000150:complications / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D009456:Neurofibromatosis 1 / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000150:complications / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D013909:Thorax; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D018396:Mucin-1