Figure 3b:

Pseudoprogression with appearance of a new lesion followed by subsequent immune-related response in a 66-year-old woman with metastatic melanoma treated with nivolumab and ipilimumab. Compared with (a) a baseline axial CT image obtained prior to the initiation of therapy, (b) a follow-up axial CT image obtained after 3 months of therapy shows a new subcutaneous lesion (arrow), indicating progressive disease according to the Response Evaluation Criteria in Solid Tumors, or RECIST; however, (c) a further follow-up axial CT image obtained after 6 months of therapy shows shrinkage of the new lesion (arrow), representing immune-related response. Note that another lesion in the deep subcutaneous tissue (*) increased at 3-month follow-up, followed by subsequent shrinkage of the lesion, also indicating immune-related response after initial increase in tumor burden.