Clinical features and 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 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 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), SUV of only lymph nodes (SUV), the most FDG-avid lesion-to-liver SUV ratio (SUR), laboratory examinations and demographics. The optimal cut-off of 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 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 and SUV 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 had higher specificity (91.9%) and relatively reasonable sensitivity (68.2%) and the cut-off point of 8.0 for the SUV had high specificity (89.2%) and relatively reasonable sensitivity (63.6%).

Conclusion: Our study identified the distinctive characteristics of the clinical manifestations, the SUR, SUV and detectability of extra-lymphatic lesions on F-FDG PET, and thus provides a new basis for distinguishing of malignant lymphoma from inflammatory lymphadenopathy in HIV-infected patients.