FDG-Avid Focal Liver Reaction From Proton Therapy in a Patient With Primary Esophageal Adenocarcinoma.

A 25-year-old man with IgA deficiency was treated with 2 months of chemotherapy and proton therapy for gastroesophageal junction adenocarcinoma. Restaging PET/CT 18 days posttherapy demonstrated 2 new foci of increased FDG uptake in the left hepatic lobe, which were favored to represent radiation injury as opposed to new metastases. Follow-up MRI with contrast 2 weeks later demonstrated hypoenhancement and T1/T2 hypointensity in the liver, without restricted diffusion, which correlated with the dominant FDG-avid focus. The hepatic lesions resolved on subsequent FDG PET/CT and MRI studies, confirming the diagnosis of acute radiation injury.