Retrospective analysis of olfactory neuroblastoma cases treated with endoscopic endonasal approach

We retrospectively reviewed nine cases of olfactory neuroblastoma in Keio University School of Medicine from 2010 to 2015. The surgical approach was the endoscopic endonasal approach, either alone or in combination with craniotomy, performed by a team of head and neck surgeons and a neurosurgeon. The distribution of patients according to the modified Kadish classification （A/B/C/D) and Dulguerov classification （T1/T2/ T3/T4) was 1/4/4/0 and 1/4/2/2. Tumors of six cases were removed by the endoscopic endonasal approach alone; three cases needed craniotomy to resect intra-dual tumors. Three-layered skull base reconstruction using fascia, pericranial flap and nasoseptal flap was used for five cases. None of the cases experienced cerebrospinal fluid leakage postoperatively. Seven patients received postoperative radiotherapy. Three cases experienced tumor recurrence, and underwent salvage surgery or radiotherapy. All cases remained alive, though the average observation time was less than 3 years. Recent reports have demonstrated that the endoscopic endonasal approach has a comparable control rate to the open approach for olfactory neuroblastoma. We believe that endoscopic endonasal skull base surgery should play a key role in the treatment of olfactory neuroblastoma in the years ahead.