Sarcoid-like reaction associated with immune checkpoint inhibitor: To be, or not to be, that is the question.

Background: Over the past decade, immune checkpoint inhibitors (ICIs) have emerged as a pivotal advance in melanoma therapy, with their use increasingly being explored and adopted across multiple other oncologic indications. Sarcoid-like reactions (SLRs) have been reported with all major classes of ICIs and most commonly in melanoma patients. It can mimic cancer progression, especially when presenting as new lymphadenopathy or pulmonary nodules on imaging.