Olfactory Carcinoma Diagnosed by Preoperative Nasal Biopsy as Cylindrical Cell Papilloma: A Case Report

Classification of neuroendocrine tumors in the paranasal sinuses is difficult, and the management of olfactory neuroblastoma with epithelial differentiation remains unclear. Recently, a group of tumors that exhibit neuroectodermal differentiation while maintaining distinct epithelial characteristics has been proposed as olfactory carcinoma, with reports indicating that these tumors have distinct clinical features and a worse prognosis than olfactory neuroblastoma. Here, we present a rare case in which an initial biopsy from the nasal cavity yielded a diagnosis of cylindrical cell papilloma, but surgical resection via combined transnasal endoscopic and transcranial approaches ultimately revealed a diagnosis of olfactory carcinoma. An accurate diagnosis is of the utmost importance for paranasal sinus tumors because it significantly impacts the treatment strategies and prognosis. In cases of olfactory carcinoma, sampling the glandular structure only may result in a misdiagnosis of papillary epithelial neoplasm. Therefore, sufficient tissue samples must be collected, and the entire tumor must be evaluated.