Mucosal Spread of Sinonasal Adenocarcinoma into the Nasolacrimal Duct Without Bony Erosion of the Nasolacrimal Canal: A Case Report

Sinonasal malignancy is a rare but recognized cause for nasolacrimal obstruction leading to epiphora. While direct mucosal spread through the nasolacrimal duct can occur in benign sinonasal tumors such as inverting papilloma, the same phenomenon has not been described in malignant lesions. The authors present a case of a low-grade nonintestinal type sinonasal adenocarcinoma centered on the inferior meatus of the sinonasal cavity, showing mucosal invasion into the nasolacrimal duct with bony expansion but no erosion of the nasolacrimal canal. The lesion was excised en bloc with a combined endoscopic and external approach with clear margins.