Corneal Keloid Caused By Posterior Polymorphous Corneal Dystrophy: First Case Report

Corneal keloid is a rare, benign, fibrovascular lesion that can develop after trauma, ocular surgery, inflammation or spontaneously. Congenital keloids occur due to abnormal neural crest development with anterior segment dysgenesis and immature collagen deposition. The commonest cause of acquired keloids is penetrating corneal trauma with iris incarceration. Although some corneal diseases have been associated with keloids such as epithelial recurrent erosion dystrophy (ERED), no studies have been published on a possible correlation between posterior polymorphous corneal dystrophy (PPCD) and keloid development. In this paper, we describe for the first time a case with this correlation that was treated at Liverpool University Hospitals (UK).

A 37-year-old Caucasian male presented in 2019 complaining of bilateral visual deterioration more severe in the left eye. He was diagnosed at the age of 17 with nonspecific bilateral corneal dystrophy during a routine eye examination.

At presentation his best corrected visual acuity (BCVA) was 0.60 logMAR in the right eye (RE) and 1.0 LogMAR in the left eye (LE). Slit lamp examination revealed bilateral PPCD with a left eye decompensated cornea. He was lost to follow-up during COVID-19 pandemic.

The patient was re-referred to our institution in 2022 complaining of LE visual deterioration and enlarging white mass. LE BCVA was hand motion. Slit lamp examination revealed a white, non-tender, smooth mass affecting his left cornea. The lesion had distinct margins. Anterior segment OCT (AS-OCT) demonstrated an intact epithelium with an underlying corneal mass separated from the stroma by a distinct plane. Total corneal thickness was 1950µm, with the keloidal lesion measuring 1330µm.

Superficial keratectomy with excisional biopsy were performed. Histological assessment confirmed dense collagenous keloidal-type scarring, absent Bowman layer, and oedematous epithelium confirming the keloidal nature of the lesion. Postoperative course was unremarkable, and the patient was satisfied with the aesthetical result. But the BCVA didn’t improve because of severe corneal decompensation due to the advanced PPCD. Slit lamp examination showed a decompensated left cornea with superior and inferior corneal neovascularization. The AS-OCT showed a smooth corneal profile without any signs of keloid recurrence. Corneal thickness improved from 1950µm preoperatively to 890µm postoperatively. Patient is scheduled for left corneal fine needle diathermy and perforating keratoplasty.

To our knowledge, this is the first case reported of a patient with PPCD developing corneal keloid.

PPCD can be associated with corneal keloid growth, especially in cases of severe corneal decompensation. This finding reinforces the concept that corneal inflammation and oedema can trigger an abnormal deposition of collagen fibres in the cornea and the development of a keloidal mass. Clinicians should be aware that, as demonstrated in our patient, severe PPCD might require keratoplasty to re-establish the corneal transparency. A simple keloid excision might be insufficient for visual rehabilitation. AS-OCT represents a useful clinical and surgical tool, but histopathological assessment is required to confirm the diagnosis.