Checkpoint inhibitor-induced immune-related sarcoidosis-like reaction

Immune checkpoint inhibitors are associated with a wide spectrum of immune-related adverse events (AE) of different severity. Immune-related sarcoidosis-like reactions are relatively rare but clinically important AEs. These abnormalities, due to the appearance of active pathological lymph nodes or nodules in other organs on radiographs, can be falsely interpreted as tumor progression or stabilization and thus affect treatment strategy, leading to unreasonably early therapy discontinuation or its unnecessary continuation. So far there were no convincing criteria for differentiation between sarcoidosis-like reaction and sarcoidosis, oncologist should be aware of this reaction and include it in the differential diagnosis in patient with suspected disease progression who are treated with immune checkpoint inhibitors.