Rapidly lethal secondary hemophagocytic lymphohistiocytosis predicted by fluorodeoxyglucose positron-emission tomography/computed tomography.

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a rare disease with either an indolent or aggressive course. A 29-year-old male presented with fever, polyarthralgias, splenomegaly, retroperitoneal adenopathy, and laboratory findings consistent with Epstein-Barr-mediated sHLH. Consistent with a prior survival analysis by Kim et al., splenic maximum standardized uptake value (SUVmax) >2.52 and bone marrow SUVmax >3.13 on 18F- fuorodeoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) predicted an aggressive disease with poor treatment response. Despite optimal treatment, the patient rapidly progressed to death within 3 months of symptom onset. This case underscores the potential lethal nature of sHLH, and the evolving role of 18FDG-PET/CT in predicting disease severity and treatment response.