BACKGROUND: CheckPoint Inhibitors (CPI) Induced arthritis (IA) is an immune related adverse event (irAEs) occurring in 0.5 to 2% of CPI-treated patients between 3 weeks up to 24 months after initiation of therapy. IA is usually described as a seronegative oligoarticular inflammatory joint disease but IA has been for long underdiagnosed and inappropriately evaluated. OBJECTIVES: To evaluate the added value of a systematic joint ultrasound assessment in these patients by the rheumatologist. […]