Exploring the role of bone marrow increased FDG uptake on PET/CT in patients with lymphoma-associated hemophagocytic lymphohistiocytosis: a reflection of bone marrow involvement or cytokine storm?

The role of 18F-2-fluoro-2-deoxy-D-glucose (FDG) uptake of bone marrow (BM) on positron emission tomography/computed tomography (PET/CT) in patients with lymphoma-associated hemophagocytic lymphohistiocytosis (LA-HLH) remains uncertain. This retrospective study included 34 LA-HLH patients who underwent both PET/CT and comprehensive BM examinations prior to treatment. Comparison between PET/CT and BM examinations for the assessment of bone marrow involvement (BMI) indicated statistical difference (p = 0.039). The specificity of PET/CT in detecting BMI was 11.1% compared to BM examinations. However, a significant correlation was found between PET parameters of BM and laboratory parameters associated with HLH, such as C-reactive protein, ferritin, fibrinogen and soluble CD25. By multivariate analysis, PET parameters of marrow were significantly associated with overall survival. The findings suggest that FDG uptake of marrow might fail to detect lymphomatous BMI, but reflected the level of cytokine storm to a certain extent and might be a prognostic factor in patients with LA-HLH.