Background: Kikuchi-Fujimoto disease (KFD), known as histiocytic necrotizing lymphadenitis, is an Asian-endemic disease of unknown etiology. Although KFD is usually self-limiting and benign, patients with prolonged systemic symptoms often have frequent hospital visits, long admission durations, and missed workdays. Immune-modulating drugs are used to shorten the clinical course in severe KFD. However, as there are no established severity markers, administration of these drugs is often arbitrary or delayed. We aimed to investigate the role of fluorine-18 fluoro-2-deoxy-D-glucose (F18-FDG) positron emission tomography/computed tomography (F18-FDG PET/CT) in KFD and to evaluate its performance as a disease severity marker. We retrospectively reviewed medical records of 31 adult patients with pathologically confirmed KFD who underwent F18-FDG PET/CT between November 2007 and April 2018 at a tertiary care referral hospital. Disease severity was assessed using the criteria based on clinical manifestations of advanced KFD. The number of systemic activated lymph nodes and severity of splenic activation were determined using semi-quantitative and volumetric PET/CT parameters.
Results: The median value of the mean splenic standardized uptake value (SUV mean ) was higher in the 23 patients with severe KFD (1.79±0.99 vs. 2.38±1.18, p =0.058). Patients with severe KFD presented with more systemically activated volume and glycolytic activity than those with mild KFD (total lesion glycolysis: 473.5±504.4 vs 201.6±363.5, p =0.024). Multivariate logistic regression showed that myalgia (odds ratio [OR], 0.035; 95% confidence interval [CI], 0.001-0.792; p =0.035), total lymph node SUV max (cutoff, 9.27) (OR, 24.734; 95% CI, 1.323-462.407; p =0.032), and spleen SUV mean (cutoff, 1.79) (OR, 37.770; 95% CI, 1.769-806.583; p =0.020) were significantly associated with severe KFD.
Conclusions: We suggest that 18 F-FDG PET/CT can be a useful tool for clinical workup in the predicting clinical course of KFD as a complement to laboratory and clinical findings to establish the severity.