Primary acquired melanosis with atypia treated with mitomycin C

The authors report the case of a 56-year-old Caucasian man who was found to have prominent melanotic conjunctival pigmentation inferotemporally in his right eye. Histopathologic evaluation disclosed malignant melanoma of the conjunctiva arising within primary acquired melanosis (PAM) associated with melanocytic atypia. The patient was treated by incisional conjunctival biopsy followed by two cycles of mitomycin C 0.04% eye drops and supplemental double-freeze thaw cryotherapy to residual foci of PAM. By 1 year following this treatment, there was no clinically apparent residual conjunctival melanosis, and visual acuity remained stable at 20/30.