Corneal collagen crosslinking (CXL) with ultraviolet-A energy plus riboflavin has become a ubiquitous treatment in early keratoconus, although its long-term safety is unknown. We describe severe sequelae in a CXL-treated patient after he underwent a standard deep anterior lamellar keratoplasty procedure.
In April 2009, a healthy 49-year-old male patient (R.H.) underwent bilateral CXL according to the Dresden protocol for progressive keratoconus stage 3. The best-corrected visual acuity did not improve over 20/100 within a postoperative period of 2 years, and contact lenses were not tolerated. Consequently, a unilateral deep anterior lamellar keratoplasty was performed, to transplant an 8-mm fully epithelialized button onto an 8-mm bed with a bared Descemet membrane (surgeon: J.H.K.).
The postoperative healing course was unusually disturbed. Sutures pulled through the recipient tissue, which required suture replacement. Portions of the epithelium sloughed off repeatedly, and bulky regrowth displayed no attachment to the Bowman membrane. Within the first weeks, the transplant became cloudy. Two biopsies were removed from the limbus area and submitted to independent histopathological laboratories, both of which diagnosed the condition as epithelial neoplasia. Pathology tests indicated conjunctival intraepithelial neoplasia, the preliminary stage of invasive squamous cell carcinoma, in the keratocyte-voided bed of the recipient.
This case suggests that CXL might hamper the ocular healing process and, combined with subsequent corneal surgery, could potentially initiate neoplasia. Further investigation is warranted to determine the safety of the combination of ultraviolet-A/riboflavin treatment and subsequent corneal tissue transplantation.