Fig. 11

Following resection of nodal metastasis in the right lower cervical region, adjuvant immune checkpoint inhibitor therapy was commenced. At 6-month surveillance ¹⁸F-FDG PET/CT, lung infiltrates were apparent on correlative CT (A). These had high ¹⁸F-FDG -avidity (B, middle panel). Serial MIP images (C) demonstrate the patchy, bilateral nature of these changes as well as generalized bone marrow activation and increased activity in both shoulders consistent with synovitis as confirmed on transaxial fused ¹⁸F-FDG PET/CT images (D, middle panel). With the introduction of corticosteroids, the pneumonitis resolved but a fatty change was noted in the liver (F, right panel) and diffuse oesophagogastric uptake was observed (G, right panel). Gastroscopy confirmed enteritis. Increased spleen to liver ratio on the late scan likely reflects a combination of reduced hepatic activity related to steatosis and splenic activation