FDG-PET/CT imaging in the management of HIV-associated multicentric Castleman’s disease

Abstract

To evaluate the role of FDG-PET/CT scanning in the management of HIV-associated multicentric Castleman's disease (MCD) a rare lymphoproliferative disorder associated with infection by human herpesvirus 8 (HHV8). Nine patients with histologically confirmed MCD underwent fused FDG-PET/CT scans at initial MCD diagnosis (n = 3), at MCD relapse (n = 4), or during remission (n = 2). All seven patients with active MCD had markedly elevated plasma HHV8 viral loads, but the patients in remission had no HHV8 viraemia. The three patients with newly diagnosed MCD were not on antiretroviral therapy at the time of imaging, but the other six were all on fully suppressive antiretroviral regimens. In the seven patients with active MCD (newly diagnosed or relapse) 33/91 lymph node groups (36%) included radiologically enlarged nodes on the CT scan, whilst 57/91 lymph node groups (63%) showed enhanced FDG uptake on the PET scan. In scans from patients in remission, there were no enlarged lymph nodes on the CT scan but 3 lymph nodes (11%) demonstrated enhanced FDG uptake. The median SUV recorded for the seven patients with active MCD was 4.8 (range 2.6-9.3) which was significantly higher than the median value of 2.5 recorded for the patients in remission (Mann-Whitney U test, p = 0.011). Despite the small number of patients, in HIV-positive individuals with active MCD, FDG-PET scans more frequently detected abnormal uptake than CT scans detected enlarged lymph nodes. FDG-PET scanning has a useful role in the management of HIV-associated MCD in selecting appropriate sites for biopsy, and in staging and monitoring these lymphoproliferations.