title: Keratinizing cyst of the lacrimal punctum.
abstract: OBJECTIVE
  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.
authors.affiliation: David G. Cogan Laboratory of Ophthalmic Pathology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yonekawa
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Jakobiec
authors.forename: Fouad R
authors.initials: FR
authors.lastname: Zakka
authors.forename: Nancy
authors.initials: N
authors.lastname: Kim
mesh_terms: D004814:Epidermal Cyst / Q000473:pathology* / Q000601:surgery; D005143:Eyelids; D006801:Humans; D007766:Lacrimal Apparatus Diseases / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged