Keratinous cyst of the palpebral conjunctiva: new observations

To describe an acquired keratinizing cyst of the palpebral conjunctiva.

Observational case report with clinical and histopathologic correlations.

A 41-year-old man presented with diffuse mild left upper eyelid swelling, eye pain, and redness in the absence of a nodule. Eversion of the eyelid revealed a whitish-gray, well-demarcated, superficial 4 × 4 mm lesion on the medial portion of the palpebral surface accompanied by a large epithelial erosion in the superior aspect of the cornea. The lesion was excised completely, sparing the tarsus. The site of excision healed completely after 1 week with no recurrence during 6 months of follow-up. Histopathologically, the lesion consisted of a round, eosinophilic, compact, acellular mass of keratin. The cyst's epithelial covering was a mixture of mostly flattened but occasionally polygonal basaloid epithelial cells, sometimes with foci of parakeratosis and pigmentation. There was no apparent keratohyalin granular layer (trichilemmal rather than epidermoid keratinization).

The pathogenesis of this peculiar lesion is hypothesized to involve a pseudogland of Henle that developed trichilemmal keratinization. It represents another easily overlooked cause of corneal epithelial erosion.