Ectopic Olfactory Neuroblastoma: Systematic Review of a Rare Clinical Entity among Sinonasal Tumors

Christopher G Lui; Ido Badash; Liyang Tang; Michelle E Mark; Pete S Batra; Bozena B Wrobel

doi:10.1055/a-1993-7790

Ectopic Olfactory Neuroblastoma: Systematic Review of a Rare Clinical Entity among Sinonasal Tumors

J Neurol Surg B Skull Base. 2023 Jan 5;85(2):109-118. doi: 10.1055/a-1993-7790. eCollection 2024 Apr.

Authors

Christopher G Lui¹, Ido Badash², Liyang Tang², Michelle E Mark³, Pete S Batra³, Bozena B Wrobel²

Affiliations

¹ Department of Otolaryngology - Head & Neck Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States.
² Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, United States.
³ Department of Otorhinolaryngology - Head and Neck Surgery, Rush University Medical Center, Chicago, Illinois, United States.

Abstract

Objectives Ectopic olfactory neuroblastoma is an uncommon manifestation of an already rare neoplasm. We aimed to systematically review the literature for cases of ectopic olfactory neuroblastoma to better characterize this rare disease entity and to present two new case reports. Methods A search of the PubMed and Embase databases was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify English-language articles reporting cases of ectopic olfactory neuroblastoma, published from 1955 through November 2021. Results Sixty-six cases of ectopic olfactory neuroblastoma were identified in 62 articles including the current review. Ectopic olfactory neuroblastoma arose in a wide age range (2-89 years) without significant sex predilection. It occurred most commonly in the ethmoid (25%), maxillary (25%), and sphenoid (16%) sinuses. Seventy-three percent of cases presented with low Hyams grade (I and II). The most common symptoms were nasal obstruction (32%) and epistaxis (32%). Paraneoplastic syndromes were observed in 27% of patients. The most common treatment was surgical resection followed by adjuvant radiotherapy. Overall, 76% of all patients were disease-free at the time of last follow-up. Locoregional recurrences and distant metastases were found in 19 and 5% of cases, respectively. Conclusion This systematic review describes previously reported cases of ectopic olfactory neuroblastoma, a disease entity with poorly understood characteristics. Physicians should consider olfactory neuroblastoma in the differential diagnosis for sinonasal masses, as their ectopic presentation may present considerable diagnostic and therapeutic difficulties. Patients with olfactory neuroblastoma may benefit from long-term follow-up and routine endoscopic examinations for surveillance of ectopic recurrences.

Keywords: ectopic; esthesioneuroblastoma; olfactory neuroblastoma; olfactory neuroepithelium; paraneoplastic syndrome; sinonasal tumor; systematic review.