title: Extra-acral cutaneous/soft tissue sclerosing perineurioma: an under-recognized entity in the differential of CD34-positive cutaneous neoplasms.
abstract: BACKGROUND
  Perineuriomas are an uncommon group of tumors composed of perineurial cells of peripheral nerve sheath lineage. Variants include soft tissue (extraneural), intraneural, sclerosing, reticular and plexiform forms. Sclerosing perineuriomas have been reported to occur almost exclusively on the hands of young men. Herein, we report three extra-acral cutaneous/soft tissue perineuriomas that show significant associated sclerosis.
  
  
  METHODS
  Skin biopsy specimens from three patients were evaluated for cytomorphology and degree of associated sclerosis, which was classified as either focal or diffuse. Immunohistochemical expression of epithelial membrane antigen (EMA), CD34 and S-100 was also assessed to facilitate further classification.
  
  
  RESULTS
  Histopathologically, the tumors showed both focal and diffuse sclerosis, and lesional cells were generally spindled in shape. Immunohistochemical staining showed diffuse positivity for CD34 and focal or diffuse positivity for EMA. The cells uniformly lacked expression of S-100 protein.
  
  
  CONCLUSIONS
  Sclerosing perineuriomas can occur in extra-acral locations and should be considered in the differential of EMA-positive cutaneous spindle-cell proliferations. It is also important to recognize that perineuriomas can express CD34 and should be considered in the differential diagnosis of CD34-positive cutaneous neoplasms.
authors.affiliation: Department of Pathology, Northshore University HealthSystem, Evanston, IL, USA.
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Fox
authors.forename: Briana C
authors.initials: BC
authors.lastname: Gleason
authors.forename: Antoinette B
authors.initials: AB
authors.lastname: Thomas
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Victor
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Cibull
mesh_terms: D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D018396:Mucin-1 / Q000378:metabolism; D018317:Nerve Sheath Neoplasms / Q000378:metabolism / Q000473:pathology*; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D018396:Mucin-1