title: The effect of surgical margins on outcomes for low grade MPNSTs and atypical neurofibroma.
abstract: OBJECTIVE
  While convention defines atypical neurofibroma as benign and low-grade malignant peripheral nerve sheath tumors (MPNSTs) as malignant, sparse outcomes data exist for these tumors. This study reviews clinical outcomes of surgically resected low-grade MPNST and atypical neurofibroma, focusing on the effect of surgical margins on outcome.
  
  
  METHODS
  This study is a retrospective review of 23 patients who underwent surgical resection of a low-grade MPNST or atypical neurofibroma. Treatment characteristics of adjuvant therapy and surgical margin were noted. Endpoints of local recurrence, presence of metastatic disease, disease-specific survival, and overall survival were reviewed.
  
  
  RESULTS
  Eighteen of 23 patients (78%) had microscopically positive margins on the resection. Disease-specific survival was 100% for both atypical neurofibroma patients and those with low-grade MPNST, regardless of surgical margin. Local recurrence in terms of recurrence of measureable disease occurred in 2/12 (16.7%) of LGMPNST patients and 1/11 (9.1%) of atypical NF patients, all of whom had microscopically positive surgical margins.
  
  
  CONCLUSIONS
  In a study dedicated exclusively to "intermediate" nerve sheath tumors, no patients developed metastatic disease nor died of disease despite a high rate of microscopically positive surgical margins (78%). While positive margins did lead to increased rates of local recurrence, these data suggest that surgeons potentially can temper their zeal for negative surgical margins in the setting of low-grade MPNST and atypical neurofibroma, as surgical morbidity may be more important than a presumed survival benefit of wide resection.
authors.affiliation: Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Bernthal
authors.forename: Angelica
authors.initials: A
authors.lastname: Putnam
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Jones
authors.forename: David
authors.initials: D
authors.lastname: Viskochil
authors.forename: R Lor
authors.initials: RL
authors.lastname: Randall
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000401:mortality / Q000601:surgery; D009442:Neurilemmoma / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D009455:Neurofibroma / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult
keywords: MPNST; atypical neurofibroma; low grade MPNST; nerve sheath tumor; neurofibromatosis