Black Henna Deposits Masquerading a Melanoma of the Plica Semilunaris

The aim of this study was to describe a rare case of conjunctival black henna accumulation that was clinically misdiagnosed as melanoma.

This retrospective case report reviewed the clinical findings and histopathologic features of a pigmented plica semilunaris lesion excised from a 63-year-old woman. The patient had a history of regular use of black henna in her childhood. The conjunctival pigmentation was present since her early teenage years but started to grow only recently.

There was a darkly pigmented mass mainly covering the plica semilunaris of the right eye with additional irregularly scattered pigmentation in the medial bulbar conjunctiva. Excisional biopsy of the plical tumor revealed nodular pigment deposits with lymphocytic infiltration. There were no neoplastic cells. The specimen stained negative for pan-keratin, CD68, and CD34. Melanin bleaching was also negative.

Long-term exposure to black henna as a hair dye may lead to subconjunctival accumulation and mimic melanoma.