Supplementary Material for: Olfactory Carcinoma, Similar yet Distinct to Olfactory Neuroblastoma: A Case Report and Literature Review

Introduction: Olfactory carcinoma (OC) is a rare tumor that is often misdiagnosed as olfactory neuroblastoma (ONB). Due to its rarity, there is no established standard treatment for OC, and there have been no reports of successful long-term follow-up treatment yet. Case Presentation: Two male patients, aged 54 and 48, presented with similar symptoms of nasal obstruction, anosmia, facial swelling, and epistaxis. Imaging in both cases revealed large, locally advanced sinonasal neoplasms. Initial biopsies were concerning for ONB, however final pathological analyses confirmed high grade OC. Treatment comprised induction chemotherapy, extensive skull base tumor resection, adjuvant chemoradiotherapy, and reconstructive surgery in both cases. The 54-year-old remains disease free at 7 years, while the 48-year-old demonstrates no evidence of disease at 8 months. Conclusion: Accurate diagnostic differentiation is imperative to optimize a treatment approach. Although outcomes with OC tend to be worse than those of ONB, effective control can be achieved with judicious concurrent use of neoadjuvant, surgery, and adjuvant treatments. Ongoing surveillance, biobanking, and genomic analysis are crucial to gain a better understanding of this complex disease.