Diffusely increased bone marrow FDG uptake in recently untreated lymphoma: Incidence and relevance

Purpose: To determine the incidence of diffusely increased bone marrow ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) uptake at positron emission tomography (PET) in recently untreated lymphoma and to assess the frequency of lymphoma-positive bone marrow biopsies (BMBs) in these patients. Methods: FDG-PET scans of all patients presenting with newly diagnosed or relapsed lymphoma were reviewed. Patients with non-focal diffusely increased bone marrow FDG uptake, who had not received therapy within 3 months, were identified. The incidences of diffusely increased bone marrow FDG uptake and the frequencies of positive posterior iliac crest BMBs among those cases were calculated. Results: The incidences of diffusely increased bone marrow FDG uptake in all lymphomas, and in Hodgkin lymphoma, aggressive non-Hodgkin lymphoma (NHL), indolent NHL, and mantle cell NHL separately, were 4.2% (23/542), 9.3% (7/75), 3.4% (8/239), 3.3% (7/214), and 7.1% (1/14), respectively, and frequencies of positive BMBs among these subgroups were 55.0% (11/20), 0.0% (0/7), 83.3% (5/6), 83.3% (5/6), and 100% (1/1), respectively. Conclusion: The incidence of diffusely increased bone marrow FDG uptake in recently untreated lymphoma is low, albeit higher in Hodgkin lymphoma than in NHL. BMB in such patients is likely to be negative in Hodgkin lymphoma, but positive in the majority of NHL cases.