# Endoscopic Removal of Sinonasal Inverted Papilloma Originating From the Posterior Ethmoid Cavity

## TL;DR

This paper describes a rare case of a benign nasal tumor originating from the posterior ethmoid cavity, successfully removed using endoscopic surgery.

## Contribution

The novelty lies in identifying a novel origin of sinonasal inverted papilloma in the posterior ethmoid cavity and demonstrating the effectiveness of endoscopic removal.

## Key findings

- The tumor originated from the posterior ethmoid cavity, a rare location for sinonasal inverted papilloma.
- Endoscopic excision was safely performed without resecting the ethmoid bone to avoid dural exposure.
- The case supports endoscopy as a preferable approach over traditional lateral rhinotomy for such tumors.

## Abstract

Sinonasal inverted papilloma is an expansive, benign mass derived from the Schneiderian membrane. It may undergo malignant transformation and most commonly originates from the maxillary sinuses or the lateral walls of the nasal corridors. This case outlines the case of a sinonasal inverted papilloma, which clearly arises from the posterior ethmoid sinus, bordering the skull base. This abnormal originating point was able to be identified during endoscopic excision of the mass and involved mucosa. The ethmoid bone was not resected as it would expose the dura mater, risking CSF leak and complications. This case further supports the use of endoscopy in the investigation of sinonasal inverted papilloma rather than the gold standard approach of lateral rhinotomy. An endoscopic approach allowed for improved safety when accessing the posterior ethmoid cavity. This case also highlights the possibility of novel origins of sinonasal inverted papilloma, such as the membrane of the posterior ethmoid cavity.