Focal Liver 18F-FDG Uptake in a Patient Who Underwent Thrombolysis for Brachiocephalic and Subclavian Thrombosis: A Potential Pitfall.

ABSTRACT: A 19-year-old woman presented with a primary mediastinal B-cell lymphoma invading the superior vena cava with associated thrombosis of the left brachiocephalic and subclavian vein. She underwent thrombolysis followed by chemotherapy. The midtreatment 18F-FDG PET/CT demonstrated important regression of the primary mediastinal B-cell lymphoma, but showed intense focal hepatic uptake in segment IV, without a corresponding lesion on ultrasonography, non-contrast-enhanced low-dose CT, and MRI. This focal uptake disappeared on a subsequent 18F-FDG PET/CT study when the radiotracer was injected in the foot, suggesting an anomalous venous return pathway that persisted despite thrombolysis.