Esthesioneuroblastoma and Olfactory Preservation: Does This Unicorn Exist and Is It Reasonable to Attempt Smell Preservation?

Object: Olfactory preservation after resection of esthesioneuroblastoma (ENB) is now possible as demonstrated by our group and other authors. However the ability of the surgeon to predict tumor involvement of the olfactory system based on radiographic imaging is unknown. This study aims to answer the question: Can a surgeon blinded to the pathology, predict whether there is unilateral involvement of the olfactory bulbs or tracts allowing for safe attempt of olfactory preservation?

Methods: 23 patients undergoing craniofacial resection from 2000 to 2016 for ENB meeting inclusion criteria of having bilateral olfactory tracts and bulbs submitted at the time of resection for pathologic margins and undergoing a primary resection of their tumor. Five board certified (2 neurosurgery, 3 otolaryngology) skull base surgeons blinded to the pathology individually reviewed the preoperative MRI scans and were then asked to predict whether there was no olfactory bulb/tract involvement, unilateral involvement potentially allowing for smell preservation, or bilateral involvement.

Results: Overall, olfactory bulb/tract involvement occurred bilaterally in 26% of cases, unilateral in 13% of cases, and no involvement in 61%. Olfactory bulb involvement occurred in both bulbs 35% of cases, unilateral in 39% of cases, and no involvement in 27% of cases sampled. When comparing physician prediction of involved tracts or bulbs, involvement was appropriate or over-called (i.e., called positive when pathology was in fact negative) in 96% of cases. One case demonstrated bilateral involvement but was under-called by three surgeons as unilateral involvement (4% of cases).

Conclusion: This study demonstrates pathologic involvement of the olfactory bulbs or tracts in 86% of cases, with involvement less than bilateral in 53% of cases. Surgeon’s ability to predict involvement that would allow management attempting smell preservation was accurate at 96%. Therefore, interpretation of imaging and proceeding with smell preservation in ENB appears reasonable in this cohort.

No conflict of interest has been declared by the author(s).