title: Rare nerve lesions of non-nerve sheath origin: a 17-year retrospective series.
abstract: BACKGROUND
  Peripheral nerve masses are frequently encountered in surgical pathology practice. However, once a peripheral nerve mass is determined not to be a nerve sheath neoplasm, differential diagnostic considerations drop off sharply.
  
  
  OBJECTIVE
  To review our experience with surgically resected nerve masses.
  
  
  METHODS
  Retrospective search of pathology database. Rare neoplasms were studied by cytogenetic analysis or gene microarray.
  
  
  RESULTS
  Four hundred fifty-eight cases were identified. After elimination of common lesions (mostly nerve sheath tumors), 37 cases (8%) remained, almost all of which were of non-nerve sheath origin: for example, hemangioma, metastatic neuroendocrine pancreatic carcinoma, meningiomas invading nerve fascicles, and primary extrarenal rhabdoid tumor and Ewing sarcoma of nerve. The latter showed rearrangement of the EWSR1 locus (22q12). The gene expression pattern of an undifferentiated sarcoma, presenting as ropelike nerve enlargement, clustered with malignant peripheral nerve sheath neoplasms but not other sarcomas or neuroepithelial tumors.
  
  
  CONCLUSIONS
  Diverse benign and malignant conditions can affect peripheral nerve.
authors.affiliation: Department of Pathology, The University of Colorado Health Sciences Center, Aurora, Colorado 80045, USA.
authors.forename: Tobin
authors.initials: T
authors.lastname: Strom
authors.forename: Bette K
authors.initials: BK
authors.lastname: Kleinschmidt-Demasters
authors.forename: Andrew
authors.initials: A
authors.lastname: Donson
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Foreman
authors.forename: Kevin O
authors.initials: KO
authors.lastname: Lillehei
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain / Q000235:genetics; D006391:Hemangioma / Q000473:pathology*; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008579:Meningioma / Q000473:pathology*; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D010190:Pancreatic Neoplasms / Q000473:pathology*; D010524:Peripheral Nervous System Neoplasms / Q000473:pathology*; D012189:Retrospective Studies; D018335:Rhabdoid Tumor / Q000473:pathology*; D012512:Sarcoma, Ewing / Q000235:genetics / Q000473:pathology*; D055815:Young Adult
chemical_list: D007143:Immunoglobulin Heavy Chains