Rationale: Pigmented lesions of conjunctiva and cornea can be observed in various conditions, from the benign nevus to malignant melanoma. Pigmented acquired melanosis (PAM) is one of them, which is a neoplastic proliferation with malignant transformation potential of melanocytes. However, to our knowledge, there has been no report as to a disturbance of corneal barrier function caused by PAM. Here we report a case of corneal PAM which led to recurrent corneal erosions.
Patient concerns: A 60-year-old woman was referred with a 4-month history of intractable recurrent epithelial erosions in the left eye. She denied any history of ocular trauma or surgery. Slit-lamp examination showed small epithelial defects and loose epithelium of overlying pigmented corneal lesions. The pigmentations were scattered in the corneal epithelial layer, from limbus to the central cornea.
Diagnosis: Conservative treatment with therapeutic contact lens and oral doxycycline did not completely cure the corneal erosion. En bloc resection of the pigmented epithelium with cryotherapy and temporary amniotic membrane transplantation were performed. Histopathologic examination demonstrated pigmented melanocytes with mild atypia, scattered mainly in the corneal basal epithelium. Immunohistochemically, the cells were positive for Melan A/MART-1 and negative for CD68 and S100. The Ki-67 proliferation index was low. Therefore, it was diagnosed as primary acquired dysplastic melanosis causing epithelial barrier dysfunction.
Interventions: We performed en bloc resection of the pigmented epithelium with cryotherapy and temporary amniotic membrane transplantation.
Outcomes: After the resection, recurrent corneal erosions and epithelial loosening were completely resolved. Although some pigmented lesions were recurred in the limbal epithelium at 8 o'clock, corneal erosion did not recur during the follow-up for 9 months.
Lessons: Our report suggests that primary acquired dysplastic corneal melanosis may cause epithelial dysfunction resulting in recurrent corneal epithelial erosions.