Immune related adverse event
20 weeks after initiation of the immunotherapy the patient showed joint swelling and pain accompanied by morning stiffness of both knees. A therapy with corticosteroids was started. After an initial improvement of the symptoms and therefore the continuation of the immunotherapy, the joint effusion returned with increasing leg edemas and joint pain. After ruling out another cause of the symptoms (such as chronic heart insufficiency, thrombosis, erysipelas, bacterial joint infection) we diagnosed an immune related oligoarthritis.