Inverted papilloma of the nasolacrimal system invading the orbit.

A 73-year-old man with a history of epiphora, discharge from the left eye, and left-sided nasal congestion underwent external dacryocystorhinostomy for nasolacrimal duct obstruction. The procedure revealed bony erosion of the majority of the lacrimal sac fossa and a large papillomatous mass filling the lacrimal sac and nasolacrimal duct. Inverted papilloma was diagnosed via biopsy. A subsequent orbitotomy with combined endoscopic medial maxillectomy was performed to remove the mass. This case illustrates the importance of including inverted papilloma, a benign but invasive neoplasm, in the differential diagnosis of nasolacrimal duct obstruction.