title: Perineural growth of benign cutaneous sweat gland tumors: a hitherto unrecognized phenomenon unassociated with malignancy.
abstract: BACKGROUND
  Cutaneous intraneural reactive epithelial proliferations mimicking malignancy include epithelial sheath neuroma, re-excision perineural invasion and reactive neuroepithelial aggregates. Nevertheless, intraneural growth of benign sweat gland tumors has not been reported before.
  
  
  OBJECTIVE
  To report a predominantly intraneural proliferation of morphologically bland sweat gland tumors, describe their clinicopathological features and correlate them with survival.
  
  
  RESULTS
  We analyzed a spiradenoma and a hidradenoma with a prominent intraneural growth, occurring on the back of the 19-year-old woman and on the arm of the 53-year-old woman. Both lesions presented as a painful and slightly raised papule. After complete excision, an uneventful clinical course was observed during the follow-up period of 52 and 54 months. Pathologically, the most striking feature was an almost exclusive intraneural growth within the peripheral nerves of the deep dermis and subcutis.
  
  
  CONCLUSIONS
  We report for the first time the predominantly intraneural growth of benign sweat gland tumors. Although their histogenesis is unknown, perineural displacement due to previous surgery or trauma, as well as development from intraneural embryological epithelial remnants remains possibilities. Long-term follow-up of our patients suggests that intraneural growth of otherwise bland sweat gland tumors does not signify malignancy. Complete excision appears to be sufficient treatment procedure.
authors.affiliation: Institute of Pathology, Medical Faculty University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Boštjan
authors.initials: B
authors.lastname: Luzar
authors.affiliation: Division of Dermatology, East Carolina University, Greenville, NC, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Shanesmith
authors.affiliation: Department of Dermatopathology, St John's Institute of Dermatology, St Thomas' Hospital, London, UK.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Calonje
mesh_terms: D018250:Acrospiroma / Q000378:metabolism / Q000473:pathology*; D006607:Adenoma, Sweat Gland / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D002272:Carcinoembryonic Antigen / Q000378:metabolism; D005260:Female; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D008875:Middle Aged; D009463:Neuroma / Q000378:metabolism / Q000473:pathology*; D010525:Peripheral Nerves / Q000378:metabolism / Q000473:pathology*; D009418:S100 Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology; D013544:Sweat Gland Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: C081876:CKAP4 protein, human; D002272:Carcinoembryonic Antigen; D008565:Membrane Proteins; D009418:S100 Proteins
keywords: adnexal neoplasm; hidradenoma; intraneural growth; prognosis; spiradenoma