Atypical Peripheral Hypertrophic Subepithelial Corneal Degeneration: A Rare Entity After Pterygium Excision

To report an atypical case of possible peripheral hypertrophic subepithelial corneal degeneration (PHSCD) in a 57 year old male patient following pterygium excision with conjunctival autograft.

Corneoplastic Unit, Queen Victoria Hospital, East Grinstead, UK

A 57 year old male patient presented with a right eye symptomatic and clinically typical nasal pterygium, for which he was treated with pterygium excision and conjunctival autograft uneventfully. Three years after his surgery, he presented with reduced visual acuity (RE 6/60 unaided) and monocular double vision. There were none of the conjunctival changes of a typical pterygium and no signs of active ocular surface inflammation in either eye. Examination revealed right eye subepithelial corneal scarring in the nasal and temporal cornea leaving a minimum clear central cornea of 2mm. The bulbar conjunctiva was completely normal. Due to visual axis involvement and associated high irregular astigmatism, a femtosecond superficial keratectomy of 80microns depth was performed with good outcome. One year later, the subepithelial scarring recurred in the same pattern but more dense, causing reduced visual acuity again. The lesion followed a clear plane on anterior segment OCT and a manual superficial keratectomy was conducted with complete removal of the scarred tissue. Histopathological examination revealed non-specific fibrotic changes. Following that, a year later the lesion recurred for a third time following the same subepithelial plane. Phototherapeutic combined with photorefractive keratectomy was performed with use of mitomycin C and a masking agent with good outcome. The patient remained asymptomatic since.

This entity is most likely a subform of PHSCD with unilateral corneal changes involving the nasal and temporal cornea. Although the corneal appearance and geographic pattern were pterygium-like, there were no conjunctival signs of pterygium recurrence, whilst the lack of elevated nodular scarred tissue is not consistent with Salzmann nodules (SN).