A case of conjunctival malignant melanoma treated with subconjunctival injection of interferon beta--efficacy and side effects

BACKGROUND: The management of conjunctival malignant melanoma remains controversial. Interferon-beta (IFN-beta) is a well-known antineoplastic agent against cutaneous malignant melanoma. CASE: A 44-year-old man was referred to Kobe University, Hospital for treatment of pigmented lesions in the corneal limbus of his right eye, first recognized in 2000 and growing gradually. FINDINGS: There were two pigmentary neoplastic lesions in the conjunctiva of his right eye, one at 9 o'clock in the limbus and the other at the inferior bulbar conjunctiva close to the fornix. Primary acquired melanosis (PAM) extended widely over the bulbar conjunctiva and the corneal surface. These findings led to the clinical diagnosis of conjunctival malignant melanoma. Systemic work-up did not detect any other neoplastic lesion. COURSE: The melanotic lesions were resected and histopathologically malignant melanoma was diagnosed. Microscopically, the tumor cells were present at the surgical margin. Melanoma recurred a half-year later at 3 o'clock in the limbus of the right eye. IFN-beta (3 million units/) was injected subconjunctivally 22 times. Side effects observed were as follows: corneal epithelial erosion, increase of the corneal thickness, lid swelling, conjunctival congestion, subconjunctival hemorrhage, and liver dysfunction. These findings were transient. Melanotic lesions, including PAM, diminished 6 months after the end of treatment. CONCLUSION: This therapeutic trial of local therapy using the subconjunctival administration of IFN-beta demonstrated excellent efficacy for the treatment of conjunctival malignant melanoma. Local and systemic side effects were seen, though transient, suggesting the necessity of long-term follow-up study.