Figure 1.

A patient with metastatic melanoma. (A) Baseline maximal intensity projection (MIP) PET images showing FDG avid left lung nodules. Note the hypermetabolic FDG uptake at the left knee joint is consistent with arthritis (dotted arrow). (B) MIP PET image at 6 months after initiation of pembrolizumab shows near complete resolution of metabolic activity of left pulmonary metastases (arrow). Note the increase in radiotracer uptake at the left knee joint (dotted arrow). (C) MIP PET image at 1 month after concomitant therapy with anti-IL-6R and pembrolizumab shows persistent near complete resolution of metabolic activity of left pulmonary metastases (arrow). Note the decrease in metabolic activity at the left knee joint (dotted arrow). (D) MIP PET image at 4 months after cessation of both anti-IL-6R and pembrolizumab shows persistent near complete resolution of metabolic activity of left pulmonary metastases. There is further decrease in metabolic activity at the left knee joint (dotted arrow). (E) MIP PET image at 7 months after cessation of ICI shows persistent near complete resolution of metabolic activity of left pulmonary metastases (arrow). The physiologic metabolic activity at the left knee joint (dotted arrow) consistent with resolution of arthritis. anti-IL-6R, anti-interleukin-6 receptor; FDG, F-fluorodeoxyglucose; ICI, immune checkpoint inhibitor; PET, positron emission tomography;