title: Unusual Intracerebral Presentation of a Myxoid Neurofibroma.
abstract: BACKGROUND
  Neurofibromas are benign nerve sheath tumors that usually affect peripheral nerves and are related to neurofibromatosis type 1; however, they have not been described as a cause of intraparenchymal brain tumor.
  
  
  METHODS
  We report a case of intracranial myxoid neurofibroma in a 19-year-old female patient manifested as an intense and progressive cephalea, followed by nausea, vomiting, photophobia, and phonophobia. Computed tomography and magnetic resonance imaging showed an extant, expansive left frontoparietal parafalcine/parasagittal tumor. Histopathologic examination determined S-100 protein and CD34 positivity, as well as sparse expression of Ki67 protein, and indicated Schwann cells with characteristic wavy nuclei and intraneural fibroblasts in a myxoid background. Together, these observations characterized the tumor as myxoid neurofibroma. The tumor was excised, and the patient recovered without deficits and with no signs of recurrence after 6 years of follow-up.
  
  
  CONCLUSIONS
  This is a novel presentation of a myxoid neurofibroma. The tumorigenesis mechanisms are likely complex and possibly involve the differentiation of Schwann cells present in adrenergic autonomic nerves in the subarachnoid arterial branches or in trigeminal nerves present in the meningeal convexity.
authors.affiliation: Department of Neurosurgery, Federal University of Sao Paulo, Sao Paulo-SP, Brazil. Electronic address: marcoscostaneuro@gmail.com.
authors.forename: Marcos Devanir Silva
authors.initials: MDS
authors.lastname: da Costa
authors.affiliation: Department of Neurosurgery, Federal University of Sao Paulo, Sao Paulo-SP, Brazil.
authors.forename: Karina
authors.initials: K
authors.lastname: Hoshino
authors.affiliation: Department of Pathology, Federal University of Sao Paulo, Sao Paulo-SP, Brazil.
authors.forename: João Norberto
authors.initials: JN
authors.lastname: Stavale
authors.affiliation: Department of Neurosurgery, Federal University of Sao Paulo, Sao Paulo-SP, Brazil.
authors.forename: Oreste Paulo
authors.initials: OP
authors.lastname: Lanzoni
authors.affiliation: Department of Neurosurgery, Federal University of Sao Paulo, Sao Paulo-SP, Brazil.
authors.forename: Sergio
authors.initials: S
authors.lastname: Cavalheiro
authors.affiliation: Department of Neurosurgery, Federal University of Sao Paulo, Sao Paulo-SP, Brazil.
authors.forename: Manoel Antonio
authors.initials: MA
authors.lastname: Paiva Neto
mesh_terms: D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D005350:Fibroma / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Benign nerve sheath tumor; Myxoid neurofibroma; Neurofibroma; Schwannoma