title: [Malignant peripheric nerve sheath tumor of the orbit: first description of orbital location in a patient with NF1].
abstract: BACKGROUND
  The malignant peripheric nerve sheath tumor (MPNST), is a malignant neoplastic lesion originated in Schwann cells of the lining sheath of peripheral nerves. This neoplasia may appear with benign or malignant heterologous components, with divergent differentiation, as the glandular one.
  
  
  OBJECTIVE
  To describe for the first time in the literature, a case of a glandular MPNST, located at the orbit and to revise the literature on this tumoral lesion.
  
  
  METHODS
  Nine year old male, with a base diagnosis of NF1, who had exophthalmos, retro-ocular pain, headache, facial asymmetry and descent of the right eyeball, that started 1 year earlier. This patient showed in the Computed Tomography an Magnetic Resonance, a well delimited, lobulated, solid mass at the eyeball, which extended to the fontal and temporal brain parenchyma. A right Fronto-temporal craniotomy was made with fronto -orbital- zygomatic resection of the tumoral lesion. Later, a dural plasty and reconstruction with titanium mesh was made at the skull base. At present, the patient is asymptomatic after 4 months of follow up. A malignant biphasic neoplastic lesion was observed, reactive in the mesenchymal elements S100, PGP 9.5, neurofilaments and vimentin. The glandular component was positive for AE1/AE3, EMA, CEA and focally for CD57. There was also reactivity to cromogranin, synaptophysin, serotonin and somatostatin. The diagnosis of Glandular MPNST was made.
  
  
  CONCLUSIONS
  For the first time in the literature a case of Glandular MPNST located at the orbit, which occurred in child with NF1, is described. This extremely uncommon neoplasia must be taken into account, in the study of biphasic malignant lesions, as its diagnosis is of great importance because of the bad prognosis of the affected patients.
authors.affiliation: Grupo de Patología del Instituto Nacional de Cancerología, Bogotá, Colombia. aromero@cancer.gov.co
authors.forename: A E
authors.initials: AE
authors.lastname: Romero-Rojas
authors.forename: J A
authors.initials: JA
authors.lastname: Díaz-Pérez
authors.forename: A
authors.initials: A
authors.lastname: Lozano-Castillo
mesh_terms: D002648:Child; D006801:Humans; D008297:Male; D018317:Nerve Sheath Neoplasms / Q000209:etiology / Q000473:pathology*; D009456:Neurofibromatosis 1 / Q000150:complications / Q000473:pathology*; D009918:Orbital Neoplasms / Q000209:etiology / Q000473:pathology*; D012196:Review Literature as Topic; D012583:Schwann Cells / Q000473:pathology