Is it really vitiligo?

Abstract

Vitiligo is a skin depigmentation disorder resulting from autoimmune destruction of melanocytes. This may occur spontaneously, in association with melanoma or as a result of immune checkpoint inhibitor (ICI) therapy. Development of vitiligo in the context of metastatic melanoma has been cited as evidence of enhanced anti-melanoma immunity. This is supported by studies that correlate vitiligo with prolonged progression-free and overall survival (1). Despite an abundance of publications speculating on this, few have defined diagnostic criteria for vitiligo and even fewer have recognised hypopigmentation as a separate entity. To highlight this we present the case of a 56-year-old man with acquired hypopigmentation after seven cycles of nivolumab therapy for metastatic melanoma. Despite having a clinical appearance of vitiligo, Wood’s lamp examination was negative. Biopsy revealed persistence of melanocytes in the epidermis. This case raises questions about reports of vitiligo in ICI therapy, and highlights the importance of clinicopathological correlation.