The majority of transformed lymphomas have high standardized uptake values (SUVs) on positron emission tomography (PET) scanning similar to diffuse large B-cell lymphoma (DLBCL)

Background: We previously correlated non-Hodgkin's lymphoma (NHL) histology with (18)fluoro-2-deoxyglucose-positron emission tomography (FDG-PET) intensity: a standardized uptake value (SUV) > 10 predicted aggressive lymphoma with > 80% certainty and an SUV > 13, with > 90% certainty. Patients and methods: To evaluate SUV in transformed lymphoma, we identified all FDG-PET scans for NHL at Memorial Sloan-Kettering Cancer 1999-2007 with (i) biopsy-proven transformation, (ii) no therapy 60 days before PET scan and (iii) FDG-PET scans no more than 60 days before or 90 days after transformation. Results: In 5 of 40 patients, the biopsy site was excised before PET; in two, only marrow was biopsied. In the remaining 33 patients, the SUV of the biopsy site ranged from 3 to 38, mean 14, median 12. Eighteen of 33 biopsies (55%) had an SUV > 10 and 16 (48%) > 13. The highest SUV in a transformed lymphoma PET scan (SUVstudy-max) ranged from 3.2 to 40, mean 15, median 12. Twenty-five of 40 patients (63%) presented with an SUVstudy-max > 10 and 20 (50%) > 13. Conclusions: Like de novo aggressive lymphomas, the majority of transformations have a high SUVstudy-max for a given pretreatment staging study, although many do not have very high values. Transformation should be suspected in indolent lymphoma with high SUVs on FDG-PET. Biopsies should be directed to the site of greatest FDG avidity.