title: Osteolytic clear cell meningioma of the petrous bone occurring 36 years after posterior cranial fossa irradiation: Case report.
abstract: OBJECTIVE
  While bone invasion and hyperostosis are frequent phenomena in meningiomas, primary intraosseous meningiomas are rare and their occurrence in the skull base is an extraordinary exception. Moreover, radiation-induced meningiomas represent a unique clinical dilemma given the fact that patients with these tumors had often received a prior full course of radiotherapy.
  
  
  METHODS
  A 42-year-old man presented with a 3-month history of progressively worsening facial asymmetry. His medical history was consistent for a posterior cranial fossa irradiation at the age of 6 years for a non-confirmed brain stem tumor. On admission his Karnofsky performance status was graded as 50% and his neurological examination showed a complete right facial nerve paralysis and hearing impairment. Computed tomography and magnetic resonance imaging demonstrated an osteolytic tumor invading the whole right petrous bone without intracranial involvement.
  
  
  METHODS
  As the tumor reached the external auditory canal, a tissue sample was obtained locally. Pathological examination of the lesion identified a grade II clear cell meningioma and the patient was consequently addressed for an intensity modulated radiation therapy. His condition remained unchanged till the most recent follow-up examination, 8 months later.
  
  
  CONCLUSIONS
  To the best of our knowledge, a radiation induced osteolytic clear cell meningioma of the petrous bone has not been previously reported. As little literature exists regarding the use of adjuvant therapies for these tumors, intensity modulated radiation therapy remains an attractive treatment option in case of pervious irradiation and general status alteration.
authors.affiliation: Department of Neurosurgery, Fattouma Bourguiba University Hospital - University of Medicine of Monastir, Monastir, Tunisia. Electronic address: atefbn@hotmail.fr.
authors.forename: A
authors.initials: A
authors.lastname: Ben Nsir
authors.affiliation: Department of Neurosurgery, The Tunisian National Institute of Neurology - University of Medicine of Tunis El Manar, Tunis, Tunisia. Electronic address: benhamoudakarim@yahoo.fr.
authors.forename: K
authors.initials: K
authors.lastname: Ben Hamouda
authors.affiliation: Department of Pathology, Fattouma Bourguiba University Hospital - University of Medicine of Monastir, Monastir, Tunisia. Electronic address: faten_hammedi@yahoo.fr.
authors.forename: F
authors.initials: F
authors.lastname: Hammedi
authors.affiliation: Department of Neurosurgery, Fattouma Bourguiba University Hospital - University of Medicine of Monastir, Monastir, Tunisia. Electronic address: kilanineurochirurgien@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Kilani
authors.affiliation: Department of Neurosurgery, Fattouma Bourguiba University Hospital - University of Medicine of Monastir, Monastir, Tunisia. Electronic address: nejib.hattab@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Hattab
mesh_terms: D000328:Adult; D020295:Brain Stem Neoplasms / Q000532:radiotherapy; D016371:Cranial Irradiation / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008579:Meningioma / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D009381:Neoplasms, Radiation-Induced / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D010014:Osteolysis / Q000000981:diagnostic imaging / Q000209:etiology*; D010579:Petrous Bone / Q000000981:diagnostic imaging / Q000473:pathology*; D012888:Skull Neoplasms / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D014057:Tomography, X-Ray Computed
keywords: Clear cell meningioma; Intensity modulated radiation therapy; Petrous bone; Radiation induced