In this issue, Badr and colleagues present "Predictive Value of FDG PET/CT Versus Bone Marrow Biopsy in Pediatric Lymphoma". This study examines the PPV and NPV of FDG PET/CT for the diagnosis of bone marrow involvement in pediatric patients with pathologically proven lymphoma (113 Hodgkin disease and 27 Non-Hodgkin lymphoma) at initial presentation. All patients had pretherapy bone marrow biopsy. The skeleton was divided into 8 segments and a 5-point scoring system was used for assessment of BM infiltration burden. Among the 140 lymphoma patients, FDG PET/CT revealed positive BM involvement in 41 patients; 2 of them were false-positive with negative BMB and regional MRI results. PPV was 95.1% for PET/CT compared with 100% with BMB. All patients with positive BM involvement by BMB were detected by FDG PET/CT. BMB was falsely negative in 25 patients (17.9%, p < 0.05). These 25 patients were properly upstaged by FDG PET/CT. NPV was 100% for PET/CT compared with 80.2% for BMB (p < 0.05). Bone marrow involvement based on a 5-point scoring system demonstrated no differences in outcomes between patients with focal BM (score 2) and extensive BM (score 5; P = 0.06). The NPV of FDG PET/CT is superior to BMB for detection of bone marrow infiltration and appropriate upstaging in patients with pediatric lymphoma. The main influence of FDG PET/CT is presence or absence of BM involvement rather than its tumor burden.