Hyperpigmented Scleroderma-like Lesions under Combined Pembrolizumab and Pemetrexed Treatment of Non-Small Lung Cancer

Immune checkpoint inhibitors (ICI) and other antineoplastic treatment regimens can trigger cutaneous immune-related adverse events (irAEs). There is a tendency for underreporting of such cases, as cutaneous irAEs are typically perceived as mild and transient. However, more serious cutaneous irAEs can occur which, despite their lower frequency, deserve attention and require specific care. Here, we report a case of extensive hyperpigmented scleroderma-like lesions (SLL) on the lower extremities under combination treatment with pembrolizumab and pemetrexed in a patient with metastatic non-small cell lung cancer. The present case in conjunction with a review of the current literature underscores the potential risk of developing SLL under treatment with anti-PD-1 antibody and/or pemetrexed. Moreover, it is possible that this particular combination treatment synergistically increases the risk of SLL. As a result, more such cases may arise in the future, as ICI/pemetrexed combination treatment might be employed more often. As drug-induced SLL usually require systemic treatment with high dose-corticosteroids, physicians should be aware of SLL as an irAE when cancer patients present with sclerotic and/or fibrotic skin lesions.