Delayed lichenoid immune-related adverse event after nivolumab discontinuation.

Immune-related adverse events (irAEs) are well-documented cutaneous toxicities associated with immune checkpoint inhibitors. They typically emerge within the first 3 months of therapy; however, delayed presentations may occur even after treatment cessation. We report a case of late-onset lichenoid dermatitis developing several months following discontinuation of anti-programmed cell death 1 therapy. Histopathological findings and clinical correlation supported the diagnosis. This case highlights the potential for post-therapy cutaneous irAEs and underscores the importance of long-term dermatological surveillance in patients treated with immune checkpoint inhibitors.