Supplementary Material for: Scleroderma Secondary to Pembrolizumab: A Case Report and Review of 19 cases of anti PD-1-induced scleroderma.

Immune checkpoint inhibitors are increasingly being used to treat various malignancies. They are known to potentially cause immune-related adverse effects, including dermatological manifestations. A rare cutaneous immune-related adverse effect is scleroderma, which has been reported to occur with anti-programmed cell death-1 (PD-1) agents such as pembrolizumab and nivolumab. This may present with skin tightening and hardening at any point during or after immunotherapy. We present the case of a 54-year-old Caucasian woman who, following 16 cycles of Pembrolizumab for breast cancer, developed clinical features of scleroderma confirmed on histology. She was initially treated with oral corticosteroids, followed by oral psoralen-UVA (PUVA), with poor response, but eventually improved with methotrexate. A literature review revealed 12 other cases of scleroderma following pembrolizumab treatment and 6 cases of scleroderma following nivolumab treatment . Scleroderma developed at different stages of pembrolizumab therapy. Although scleroderma is not commonly drug-induced, pembrolizumab and nivolumab may be a rare causes and it is important to elicit an accurate drug history, including immunotherapy, in such cases.