Role of 18F-FDG PET/CT in the Management of Patients Affected by HHV-8-Associated Multicentric Castleman’s Disease

Abstract

Our aim was to investigate the usefulness of 18fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in the diagnosis, treatment response evaluation, and follow-up of human herpesvirus-8 (HHV-8)-associated multicentric Castleman’s disease (MCD). Fifteen patients with histologically diagnosis of HHV-8-associated MCD were retrospectively included. For all patients, a ¹⁸F-FDG PET/CT scan was performed before any treatment for diagnosis and PET/CT scans after Rituximab (4 cycles) for the evaluation of treatment response; moreover, 22 PET/CT were performed during the follow-up to check disease status. To evaluate treatment response, we applied Deauville criteria. PET/CT findings were compared with other conventional imaging (CI) findings. At diagnosis, ¹⁸F-FDG PET/CT showed an increased FDG-uptake in all cases corresponding to lymph nodes and confirming the MCD. The average SUVmax of the FDG avid lesions were 8.75, average lesion-to-liver SUVmax ratio was 3.6, and average lesion-to-blood pool SUVmax ratio was 3.9. After first-line therapy, ¹⁸F-FDG PET/CT resulted negative (Deauville score < 4) in seven patients and positive in the remaining eight (Deauville score 4–5). A negative restaging PET/CT was associated with a lower risk of relapse. During follow-up, PET/CT detected the presence of relapse or progression in 5 (23%) cases with an accuracy higher than CI. ¹⁸F-FDG PET/CT seems to be an useful tool in studying HHV-8-associated MCD both at diagnosis and during follow-up.