title: Sphenoid sinus brown tumor of secondary hyperparathyroidism: case report.
abstract: OBJECTIVE
  Brown tumor is a misnomer for a reparative cellular process caused by primary or, less commonly, secondary or tertiary hyperparathyroidism. Atypical involvement of the base of the cranium in the area of the sphenoid sinus and the orbit is exceedingly rare and may produce a neurological deficit as a primary clinical presentation. Those neurosurgeons dealing with cranial base and pituitary lesions should be aware of this disease entity, and it should be listed in the differential diagnosis.
  
  
  METHODS
  A 21-year-old woman with end-stage renal failure on chronic dialysis was referred to the Department of Neurosciences at King Faisal Specialist Hospital and Research Centre with a 4-month history of progressive impairment of vision, associated with headache and nausea. Computed tomography and magnetic resonance imaging demonstrated an expansive mass lesion in the sphenoid sinus with erosion of the sellar floor and posterior medial wall of the orbit causing compression of the optic nerves. The biochemical laboratory studies showed elevation of parathyroid hormone and confirmed the diagnosis of hyperparathyroidism.
  
  
  METHODS
  The transnasal-transsphenoidal approach was used for extensive microsurgical removal of the lesion. The postoperative course was uneventful, and the improvement in vision was dramatic.
  
  
  CONCLUSIONS
  Brown tumor, although rare, should be listed in the differential diagnosis of expansive mass lesions in the area of the sphenoid sinus and cranial base. The management is multidisciplinary, and therapeutic options should target the underlying cause.
authors.affiliation: Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
authors.forename: I
authors.initials: I
authors.lastname: Kanaan
authors.forename: M
authors.initials: M
authors.lastname: Ahmed
authors.forename: A
authors.initials: A
authors.lastname: Rifai
authors.forename: J
authors.initials: J
authors.lastname: Alwatban
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000150:complications*; D008279:Magnetic Resonance Imaging; D010254:Paranasal Sinus Diseases / Q000175:diagnosis / Q000209:etiology / Q000601:surgery; D013101:Sphenoid Sinus / Q000473:pathology / Q000601:surgery*