THE DELICATE BALANCE OF MMC: TREATING NEOPLASIA WITHOUT HARMING THE CORNEA

Conjunctival intraepithelial neoplasia (CIN) is the most common form of ocular
surface squamous neoplasia. The classic treatment is complete excision, but recurrence rates are high. As
such, antineoplastic drugs like mitomycin C (MMC) are used with the purpose of reducing the recurrence
rate. MMC is an antimetabolite that alkylates DNA and disrupts the production of RNA. Its’ side effects
include ocular pain, possible limbal stem cell loss, and other ocular surface toxicity. The purpose of this work
is to report a case of neurotrophic keratitis in the setting of a conjunctival neoplasia’s treatment with
mitomycin and its’ management.

Oculoplastics and Ocular Surface Unit, Department of Ophthalmology, ULS São José

Case report

A 72-year-old male with a history of topical MMC use for over one year was referred for evaluation of a conjunctival lesion in the right eye. At presentation, no residual neoplastic lesion was noted, and MMC was discontinued. One month later, a pagetoid corneal lesion appeared; biopsy confirmed CIN with moderate dysplasia. Four cycles of MMC 0.04% were administered. Although complete regression of the neoplasia was achieved, the patient developed persistent epithelial defect consistent with stage II NK. Treatment with preservative-free lubricants, topical antibiotics, corticosteroids, and a therapeutic contact lens led to complete corneal healing after two months.

This case highlights a rare but serious complication of MMC therapy. While MMC successfully controlled CIN, it induced neurotrophic keratitis, emphasizing the importance of close follow-up and early management to prevent irreversible ocular surface damage.