Limbal Cysts: A Subset Exhibiting Cornea-Specific Cytokeratins

Two cases of limbal cysts lined by nonkeratinizing epithelium were studied with a panel of cytokeratins. One was a long-standing lesion in a 30-year-old man, whereas the other was excised from a 40-year-old man following pterygium surgery. Each cyst was immunostained with a panel of cytokeratins that were specific exclusively and separately for corneal and conjunctival epithelia. The epithelial lining of each cyst was CK12 positive for corneal epithelium and CK13 negative for conjunctival epithelium. It is hypothesized that a subset of corneoscleral cysts contain corneal epithelium, probably derived from a type of limbal stem cell differentiation.