F-18 FDG PET/CT for the characterization of Castleman's disease according to clinical subtype

Objectives Castleman‘s disease (CD) is an uncommon lymphoproliferative disease. CD is usually classified into two distinct subtypes; unicentric and multicentric. The abjective of our study is to review the CT finding and to assess the tumor glucose metabolism of the unicentric and multicentric CD.

Methods From June 2006 to August 2009, we studied 9 patients who were diagnoses as having Castleman‘s disease (M:F=3:6, age=44.56±20.79 years). All patients were performed preoperative F-18 FDG PET/CT and 5 patients were performed follow-up F-18 PET/CT. The SUVmax was calculated for each FDG uptake focus.

Results Among the 9 patients with CD, 6 patients were unicentric type and 3 patients multicentric type. In unicentric CD, 3 lesions were located in the mediastinum; 3 lesions in abdominal cavity (1=portocaval lymph node, 1=retroperitoneum, 1=spleen). The tumor size were variable from 2cm to 10cm (4.62±3.40 cm). On the CT, majority of the lesions were showed homogeneously intense contrast enhancement, but some lesions were showed heterogeneous appearance, especially lesions larger than 5 cm. In 3 patients with multicentric CD were showed generalized lymphadenopathies (LAPs) between neck and inguinal region with variable size and homogeneously enhancement. In metabolism pattern, the unicentric CD were noted low glucese metabolism (SUVmax=3.14±0.86) and multicentric CD showed high glucose metabolism (SUVmax=9.30±3.96). The patients with multicentric CD were treated with steroid and chemotherapy. A follow-up PET/CT scan demonstrated good response for therapy.

Conclusions Most Castleman's disease lesions appeared as well-defined mediastinal or abdominal mass or LAPs and showed good enhancement. According to the clinical subtypes, the unicentric CD were noted low glucese metabolism and multicentric CD were noted high glucose metabolism. In multicentric CD, F-18 PET/CT was also useful in assessing therapy response