Olfactory neuroblastoma (esthesioneuroblastoma): report of six cases treated by a novel combination of endoscopic surgery and radiosurgery.

Microsurgical techniques have considerably improved the results of surgical treatment for esthesioneuroblastoma (olfactory neuroblastoma). Nevertheless, these rare tumours of the frontal skull base are still associated with high rates of tumour recurrence and mortality, thus remaining a challenge even for experienced surgeons. A novel therapeutic approach that combines endoscopic sinus surgery and radiosurgery (gamma knife) is presented here. Six patients (3 males, 3 females) aged between 27 and 75 years (median 38 years) were treated between August 1993 and July 1999. Following paranasal and nasal endoscopic sinus surgery, marginal irradiation doses ranging from 16 to 34 Gy were applied radiosurgically involving up to 7 isocentres. At present, the median follow-up period is 57 months (range: 9 - 79 months). Without mortality, tumour control was achieved in all patients. One patient, who had to undergo additional craniotomy because of extensive neoplastic infiltration, developed postoperative liquorrhea. In another case the clinical course was complicated by a bilateral frontal sinusitis. All patients complained of nasal discharge and crusts. However, a preoperative Karnovsky Index ranging from 80 to 100 % remained stable in four patients whereas an improvement was observed in two patients. Based on the favourable results observed so far, the combination of endoscopic sinus surgery and radiosurgery can be considered as promising new option for the treatment of esthesioneuroblastoma that merits further investigation.