Abstract
We studied the clinical relevance of ^18^F‐fluorodeoxyglucose (^18^F‐FDG) uptake in patients with primary gastric lymphoma underwent positron emission tomography (PET)/ computed tomography (CT) scan. Forty‐two patients with primary gastric lymphoma were analysed: 32 diffuse large B‐cell lymphomas (DLBCL) and 10 extranodal marginal zone B‐cell lymphomas of mucosa‐associated lymphoid tissue (MALT lymphomas). The PET/CT scans were compared with clinical and pathologic features, and the results of CT and endoscopy. Nine patients were up‐staged based on the results of their PET/CT scan compared to CT (seven DLBCLs, two MALT lymphomas) while six patients were down‐staged by the PET/CT scan. The standard uptake value (SUV) was used as an indicator of a lesion with a high metabolic rate. The high SUVmax group, defined as an SUVmax ≥ median value, was significantly associated with an advanced Lugano stage (p < 0.001). Three patients with DLBCL, who showed an initially high SUVmax, died of disease progression. Among 24 patients for whom follow‐up PET/CT scan with endoscopy was performed, 11 patients with ulcerative or mucosal lesions showed residual ^18^F‐FDG uptake. All of these gastric lesions were grossly and pathologically benign lesions without evidence of lymphoma cells. In conclusion, PET/CT scan can be used in staging patients with primary gastric lymphoma; however, the residual ^18^F‐FDG uptake observed during follow‐up should be interpreted cautiously and should be combined with endoscopy and multiple biopsies of the stomach. Copyright © 2009 John Wiley & Sons, Ltd.