18F-FDG PET/CT imaging features of patients with multicentric Castleman disease

Objective: The aim of this study is to investigate the role of 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) in the evaluation of multicentric Castleman disease (MCD).

Methods: Thirty-five patients with pathologically confirmed MCD who underwent 18F-FDG PET/CT were retrospectively included. The FDG uptake and CT findings of lymph nodes, pulmonary involvement, spleen, and bone marrow were assessed and the maximum standardized uptake value (SUVmax) of each lesion was measured. The locations of lymph nodes were also evaluated.

Results: 18F-FDG PET/CT showed increased uptake in multiple nodal regions in 34 out of 35 MCD patients. The most frequently involved nodal sites were the cervical, iliac, axillary, and inguinal areas, and the least common was paraaortic and abdominal nodes. The involved lymph nodes were not confluent and presented a relatively symmetric pattern on PET/CT images. The highest SUVmax of lymph nodes per patient ranged from 2 to 19 with a mean value of 5.61 ± 3.12. Pulmonary manifestation including cysts, nodules, and interstitial lung disease were found in 10 patients, eight of whom demonstrated mild to moderate uptake in the lungs. 18F-FDG PET/CT also revealed other findings including hypermetabolic spleen (n = 8) and bone marrow (n = 23), elevated uptake in salivary glands (n = 8). Four patients also underwent follow-up PET/CT scans after therapy, and three of them displayed decreased metabolism.

Conclusion: 18F-FDG PET/CT is a useful tool in the diagnosis, evaluation, and follow-up of MCD by providing systemic manifestations of lymphadenopathy, pulmonary involvement, and hypermetabolic spleen or bone marrow. Furthermore, the lymphadenopathy in MCD presented a predominantly peripheral distribution, relatively symmetric, moderately hypermetabolic, and not confluent pattern on 18F-FDG PET/CT.