Clinical features and 18 F-FDG PET/CT for distinguishing of malignant lymphoma from inflammatory lymphadenopathy in HIV-infected patients

Background It is vital to distinguish between inflammatory and malignant lymphadenopathy in human immunodeficiency virus (HIV) infected individuals. The purpose of our study was to differentiate the variations in the clinical characteristics of HIV patients, and apply 18 F-FDG PET/CT parameters for distinguishing of malignant lymphoma and inflammatory lymphadenopathy in such patients. Methods This retrospective cross-sectional study included 59 consecutive HIV-infected patients who underwent whole-body 18 F-FDG PET/CT. Of these patients, 37 had biopsy-proven HIV-associated lymphoma, and 22 with HIV-associated inflammatory lymphadenopathy were used as controls. The determined parameters were the maximum of standard uptake value (SUV max ), SUV max of only lymph nodes (SUV LN ), the most FDG-avid lesion-to-liver SUV max ratio (SUR max ), laboratory examinations and demographics. The optimal cut-off of 18 F-FDG PET/CT value was analyzed by receiver operating characteristic curve (ROC). Results Considering the clinical records, the Karnofsky Performance Status (KPS) scores in patients with inflammatory lymphadenopathy were obviously higher than those in patients with malignant lymphoma (P = 0.015), whereas lymphocyte counts and lactate dehydrogenase (LDH) were obviously lower (P = 0.014 and 0.010, respectively). For the 18 F-FDG PET/CT imaging, extra-lymphatic lesions, especially digestive tract and Waldeyer’s ring, occurred more frequently in malignant lymphoma than inflammatory lymphadenopathy. Furthermore, the SUR max and SUV LN in malignant lymphoma were markedly higher than those in inflammatory lymphadenopathy (P = 0.000 and 0.000, respectively). The cut-off point of 3.1 for SUR max had higher specificity (91.9%) and relatively reasonable sensitivity (68.2%) and the cut-off point of 8.0 for the SUV LN had high specificity (89.2%) and relatively reasonable sensitivity (63.6%). Conclusion Our study identified the distinctive characteristics of the clinical manifestations, the SUR max , SUV LN and detectability of extra-lymphatic lesions on 18 F-FDG PET, and thus provides a new basis for distinguishing of malignant lymphoma from inflammatory lymphadenopathy in HIV-infected patients.