Olfactory neuroblastomas are relatively uncommon malignant tumors that arise from the olfactory (smelling) nerve and typically grow into the ethmoid sinus (air sinuses) below the frontal lobes. Some olfactory neuroblastomas grow into the brain cavity around the region of the cribiform plate in the frontal fossa. These tumors tend to be locally invasive. They occur equally in men and women and occur in adults and less often in adolescents.

Olfactory neuroblastomas typically cause loss of sense of smell (anosmia), epistaxis (nasal bleeding), nasal congestion/obstruction and headache. If the tumor invades the dura and intracranial space, it can cause seizures.

These tumors are typically diagnosed by magnetic resonance imaging (MRI) or computer tomography (CT) scans of the brain and paranasal sinuses.

Their aggressive nature typically warrants multimodality treatment including surgical removal through an endonasal approach or combined cranio-facial approach, radiotherapy, and chemotherapy in some cases.