[An atypical medial canthal mass: a case of lacrimal sac inverted papilloma with literature review].

Background: Lacrimal sac localization of an Inverted Papilloma is extremely rare and no risk factors are reported in literature.

History: A chemical trauma was followed by a painless, growing mass in the medial canthal area associated with epiphora.

Findings: Rhinoendoscopy, Computed Tomography and Magnetic Resonance showed a well-defined mass in left lacrimal fossa extended to the nasolacrimal duct.

Treatment: An endoscopic resection and a dacryocystorhinostomy were performed.

Conclusion: The aim of the present study is to show an atypical presentation of a well-known tumor along with a suspicious risk factor and to lead otolaryngologists to consider an inverted papilloma of the lacrimal system among lesions causing lateral nasal swelling.