title: Endoscopic endonasal surgical management of chondrosarcomas with cerebellopontine angle extension.
abstract: OBJECTIVE
  Skull base chondrosarcomas are slow-growing, locally invasive tumors that arise from the petroclival synchondrosis. These characteristics allow them to erode the clivus and petrous bone and slowly compress the contents of the posterior fossa progressively until the patient becomes symptomatic, typically from cranial neuropathies. Given the site of their genesis, surrounded by the petrous apex and the clival recess, these tumors can project to the middle fossa, cervical area, and posteriorly, toward the cerebellopontine angle (CPA). Expanded endoscopic endonasal approaches are versatile techniques that grant access to the petroclival synchondrosis, the core of these lesions. The ability to access multiple compartments, remove infiltrated bone, and achieve tumor resection without the need for neural retraction makes these techniques particularly appealing in the management of these complex lesions.
  
  
  METHODS
  Analysis of the authors' database yielded 19 cases of skull base chondrosarcomas; among these were 5 cases with predominant CPA involvement. The electronic medical records of the 5 patients were retrospectively reviewed for age, sex, presentation, pre- and postoperative imaging, surgical technique, pathology, and follow-up. These cases were used to illustrate the surgical nuances involved in the endonasal resection of CPA chondrosarcomas.
  
  
  RESULTS
  The male/female ratio was 1:4, and the patients' mean age was 55.2 ±11.2 years. All cases involved petrous bone and apex, with variable extensions to the posterior fossa and parapharyngeal space. The main clinical scenario was cranial nerve (CN) palsy, evidenced by diplopia (20%), ptosis (20%), CN VI palsy (20%), dysphagia (40%), impaired phonation (40%), hearing loss (20%), tinnitus (20%), and vertigo/dizziness (40%). Gross-total resection of the CPA component of the tumor was achieved in 4 cases (80%); near-total resection of the CPA component was performed in 1 case (20%). Two patients (40%) harbored high-grade chondrosarcomas. No patient experienced worsening neurological symptoms postoperatively. In 2 cases (40%), the symptoms were completely normalized after surgery.
  
  
  CONCLUSIONS
  Expanded endoscopic endonasal approaches appear to be safe and effective in the resection of select skull base chondrosarcomas; those with predominant CPA involvement seem particularly amenable to resection through this technique. Further studies with larger cohorts are necessary to test these preliminary impressions and to compare their effectiveness with the results obtained with open approaches.
authors.affiliation: Department of Neurosurgery-Head & Neck Surgery, Wexner Medical Center at The Ohio State University, Columbus, Ohio.
authors.forename: Paulo M
authors.initials: PM
authors.lastname: Mesquita Filho
authors.forename: Leo F S
authors.initials: LF
authors.lastname: Ditzel Filho
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Prevedello
authors.forename: Cristian A N
authors.initials: CA
authors.lastname: Martinez
authors.forename: Mariano E
authors.initials: ME
authors.lastname: Fiore
authors.forename: Ricardo L L
authors.initials: RL
authors.lastname: Dolci
authors.forename: Bradley A
authors.initials: BA
authors.lastname: Otto
authors.forename: Ricardo L
authors.initials: RL
authors.lastname: Carrau
mesh_terms: D000328:Adult; D000368:Aged; D002530:Cerebellopontine Angle / Q000473:pathology*; D002813:Chondrosarcoma / Q000601:surgery*; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D009666:Nose / Q000601:surgery*; D012189:Retrospective Studies; D019292:Skull Base Neoplasms / Q000601:surgery*
keywords: CN = cranial nerve; CPA = cerebellopontine angle; EEA = endoscopic endonasal approach; ICA = internal carotid artery; IMRT = intensity-modulated radiation therapy; cerebellopontine angle; chondrosarcoma; endonasal; endoscopie; skull base