Fig. 3

a Baseline whole-body MIP image demonstrating intense FDG uptake in a large retroperitoneal mass (red arrow) compatible with patient’s follicular lymphoma. b Representative axial PET/CT image from the same time point as in (a) showing the large, FDG-avid mass (red arrow). Note the common bile duct stent (red arrowhead) that is markedly anteriorly displaced by the lymphomatous mass and explains the patient’s presentation with obstructive jaundice. c Whole-body MIP image following three cycles of R-CHOP shows no residual metabolically active lymphoma. d Representative axial PET/CT image from the same time point as in (c) is notable for the presence of minimal residual abnormal soft tissue in the retroperitoneum (red arrow, Lugano 2), with uptake equal to blood pool, compatible with a complete metabolic response. The common bile duct stent is in near-orthotopic location now that the retroperitoneal mass has dramatically reduced in size (red arrowhead). e Whole-body MIP image at the end of therapy, again demonstrating no metabolically active tumor. f Representative axial PET/CT image from the same time point as in (e) again depicts the complete metabolic response (Lugano 1) and also the removal of the common bile duct stent