Vitiligo-like depigmentation after pembrolizumab treatment in patients with non-small cell lung cancer: a case report

Immune checkpoint inhibitors (ICIs) targeting programmed death-1 (PD-1) pathway have significantly improved outcomes for patients with a variety of malignancies, including non-small cell lung cancer (NSCLC). In contrast, the incidence of immune-related cutaneous adverse events such as vitiligo have been on the rise because of the increasing use of ICIs. Vitiligo-like depigmentation has been reported in only 2.0% to 8.3% of patients with melanoma and is considered a favorable prognostic factor. However, it has been rarely reported in patients with non-melanoma malignancies. We describe a case of vitiligo-like skin depigmentation after pembrolizumab use in a patient with stage IV NSCLC. Multiple ill-defined painless and non-pruritic depigmented patches appeared on the patient's hands, scrotum, and lower lip after five months of pembrolizumab. We continued treatment with pembrolizumab 2 mg/kg for 14 months with close monitoring of vitiligo lesions until the progression of brain metastasis, but the vitiligo-like depigmentation did not improve by the combined excimer laser and topical corticosteroid therapy. Clinicians should be aware that immune-related cutaneous adverse events such as vitiligo-like depigmentation are not limited to cases of melanoma but arise as a direct result of anti-PD-1 therapy.