FDG PET Images of Pseudoprogression After Nivolumab-FOLFOX Chemotherapy in a Gastric Cancer Patient.

A 60-year-old man diagnosed with gastric adenocarcinoma underwent FDG PET/CT. After completing 9 cycles of combination chemotherapy with nivolumab and FOLFOX, he had multiple new nodular uptakes in the bilateral cervical chains and mediastinum. The pathology of the right neck node confirmed reactive lymph node hyperplasia without evidence of malignancy, suggesting pseudoprogression after immunotherapy. It is worthwhile to report these PET image patterns, as they could significantly influence clinical decision-making.