An Uncommon Encounter: Metastatic Olfactory Neuroblastoma in an Adult Male

Olfactory neuroblastoma is an extremely rare malignancy of the sinonasal tract. It is a neuroectodermal tumor, originating from the olfactory epithelium of the nasal and sinus cavities. Due to its rarity, no standard of care treatments have been established to date. We present a case involving a young adult who presented for evaluation of a palpable cervical lymph node. Nasal endoscopy and Magnetic Resonance Imaging (MRI) of the visceral cranium showed a space-occupying lesion in the right nasal cavity, along with a suspicious right submandibular lymph node block. Fine Needle Biopsy (FNB) of the cervical lymph node was suggestive of a small round blue cell tumor, confirming the diagnosis of olfactory neuroblastoma. Staging Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) scan identified multiple bone-lytic metastases. The patient was treated with three lines of systemic therapy, but unfortunately, he succumbed to his disease. This case aims to highlight the intricacies of diagnosing and treating one of the rarest malignancies of the head and neck, particularly in the metastatic setting.