Potentially life-threatening primary acquired melanosis

Primary acquired melanosis is an acquired conjunctival pigmentation seen in Caucasians. It presents as a diffuse, patchy, unilateral area of pigmentation that can be flat or nodular. Other melanotic lesions such as ocular melanosis, argyrosis, congenital conjunctival melanosis can be confused with primary acquired melanosis. Diagnosis and management of primary acquired melanosis is critical since it is potential life-threatening. A 51-year-old while male presented with unilateral, diffuse, patchy pigmentation first noted 10 years prior. Slit lamp examination revealed a 4 mm x2 mm area of temporal bulbar conjunctival pigmentation extending to the limbus in the right eye. A biopsy was performed and pathologic examination disclosed primary acquired melanosis with atypia. Topical mitomycin-C therapy was initiated. Because of the large size and diffuse nature of the pigmentation, mitomycin-C was preferred since surgical excision would be destructive and has related risks of scarring, goblet cell loss, and associated side effects such as dry eye and ulceration. Two months, following treatment with mitomycin-C, significant clinical improvement was observed. A careful patient history is key in diagnosis primary acquired melanosis including a detailed history including onset, duration, stability, and progression of the pigmentation. All cases of primary acquired melanosis should be referred for biopsy. If atypia is found, traditional treatment includes surgical removal or cryotherapy. However, if the area is large side effects can occur. Mitomycin-C eliminates these potential side effects and can be used to successfully treat primary acquired melanosis.