Sinonasal oncocytic Schneiderian papilloma limited to the inferior turbinate: a rare case.

Sinonasal oncocytic papilloma is a rare benign epithelial tumor arising from the Schneiderian mucosa, accounting for 3%-5% of all sinonasal papillomas. We present a case of a 67-year-old man with a history of non-Hodgkin lymphoma who presented with a one-year history of frontal and parietal headache, nasal obstruction, and discharge. Endoscopic examination revealed a polypoid lesion arising from the right inferior turbinate-an exceptionally uncommon site. Computed tomography demonstrated a well-circumscribed mass confined to the inferior turbinate without bone erosion, while a positron emission tomography scan with a computed tomography revealed no fluorodeoxyglucose uptake. Histopathological evaluation confirmed the diagnosis of sinonasal oncocytic papilloma, characterized by oncocytic epithelium with eosinophilic cytoplasm and intraepithelial microcysts. The patient underwent endoscopic partial turbinectomy with complete excision of the lesion. Postoperative recovery was uneventful, and follow-up nasal endoscopy at one year showed complete mucosal healing without evidence of recurrence or polypoid degeneration. This case highlights an unusual localization of sinonasal oncocytic papilloma and underscores the diagnostic challenges associated with its differentiation from inflammatory and neoplastic lesions. It further emphasizes the importance of correlating histopathologic findings with imaging modalities, including a positron emission tomography scan with a computed tomography, in achieving an accurate diagnosis and optimal management of this rare entity.