Keratinizing Cyst of the Lacrimal Punctum

Purpose To describe the clinical and histopathologic features of the first reported punctal keratinizing cyst. Methods Observational case report with clinical findings and paraffin-embedded tissue stained with hematoxylin and eosin. Results A 54-year-old man presented with an outpouching in the region of the left upper lacrimal punctum. Microscopic examination revealed a cyst filled with needle-like keratin located in the proximal subpunctal canaliculus, with a small, mostly effaced punctal orifice with focal extrusion of keratin. The epithelial wall was composed of a crenellated, multilaminar, keratinizing squamous epithelium. There was no associated inflammation or foreign bodies. Conclusions To the best of our knowledge, a punctal canalicular cyst, or any ectasia of the canaliculus or the lacrimal sac, has never before been reported primarily to contain keratin. As a new entity, this report broadens the differential diagnosis for lesions of the lacrimal drainage system.