title: Subdiaphragmatic and intrathoracic paraspinal malignant peripheral nerve sheath tumors: a clinicopathologic study of 25 patients and 26 tumors.
abstract: BACKGROUND
  To determine the effects of anatomic site on the presentation and diagnosis of malignant peripheral nerve sheath tumors (MPNSTs) and on the treatment and outcomes of the patients, the authors initiated a study of these tumors at different sites. An earlier report described MPNSTs of the buttock and lower extremity, and the current series analyzes those presenting at intrathoracic (IT) and subdiaphragmatic (SD) paraspinal sites.
  
  
  METHODS
  The authors reviewed data on patients with paraspinal MPNSTs who were seen at Memorial Hospital during the period 1960-1995 and for whom histologic slides were available. Various clinicopathologic parameters and their effects on patient outcomes were examined.
  
  
  RESULTS
  Twenty-five patients with 26 tumors were evaluated. Seven tumors were IT and 19 were SD; 60% of the patients had neurofibromatosis type 1 (NF1). Most patients presented with pain, and a diagnostic delay (of 3 months to 2 years) was often noted. Mean tumor sizes for SD and IT tumors were 14.3 cm and 6.6 cm, respectively. Most MPNSTs were composed of spindle cells in fascicles. Twenty-seven percent exhibited divergent differentiation. Twenty-four tumors were high grade, and a low grade component was identified in 8 tumors. Surgical resection was attempted for 23 tumors (88%), but complete resection was achieved in only 6 cases (23%). Eighty percent of the patients died of their tumors, 2-year and 5-year survival rates were 35% and 16%, and median survival was 8.5 months. Significant prognostic factors were tumor size <5 cm, the presence of a low grade component, and complete tumor resection.
  
  
  CONCLUSIONS
  Paraspinal MPNSTs have more aggressive behavior than peripherally located tumors, mainly because of the difficulty encountered in resecting them completely. Prognoses of patients with MPNST at this site appear to be affected by resection status, tumor size, and tumor grade.
authors.affiliation: Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
authors.forename: H P
authors.initials: HP
authors.lastname: Kourea
authors.forename: M H
authors.initials: MH
authors.lastname: Bilsky
authors.forename: D H
authors.initials: DH
authors.lastname: Leung
authors.forename: J J
authors.initials: JJ
authors.lastname: Lewis
authors.forename: J M
authors.initials: JM
authors.lastname: Woodruff
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018317:Nerve Sheath Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D010524:Peripheral Nervous System Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D015996:Survival Rate; D013899:Thoracic Neoplasms / Q000473:pathology