Progressive Nonulcerative Paracentral Keratolysis Associated with Elevated Corneal Metalloproteinases

Purpose. We report a patient with progressive idiopathic, nonulcerative, noninflammatory, avascular, bilateral, paracentral and peripheral corneal thinning monitored for 13 years. Methods. Because of progressive corneal thinning, the patient underwent several surgical procedures, including an arcuate lamellar keratectomy with suturing, bilateral 15-mm diameter onlay lamellar corneoscleral epikeratoplasties, and removal of interface epithelial tissue. Over time, the keratolysis also thinned the donor stroma, requiring a lamellar tectonic graft. A biopsy was performed of the patientʼs cornea and conjunctiva, and the tissue was analyzed for proteolytic enzymes. Results. Increased quantities of matrix metalloproteinases (57 and 63 kDa) were extracted from the patientʼs normal-appearing and abnormal corneal samples but not from adjacent conjunctiva and sclera or normal controls. This is the first reported case with these clinical and laboratory findings. Conclusion. A previously undescribed progressive idiopathic paracentral keratolysis is associated with increased quantities of matrix metalloproteinases. Clinical management requires tectonic corneal surgery