Imaging findings of Castleman disease of the abdomen and pelvis

The purpose of this study was to analyze the characteristic features of Castleman disease in the abdomen and pelvis as suggested by imaging findings in order to deepen the recognition and understanding of this rare disease.

A group of ten patients with pathologically proven Castleman disease in the abdomen (n = 9) and pelvis (n = 1) were included in this study. Patients were 18∼56-year-old (mean = 40); seven of them were men and three were women. Imaging findings (CT&MRI, n = 4; only CT, n = 4; only MRI, n = 2) were retrospectively reviewed and correlated with clinical and pathologic findings.

The lesions were divided into those with localized Castleman (n = 9) and disseminated Castleman (n = 1). The pathologic subtype of all nine cases of localized disease was hyaline vascular with six patients showing a solitary mass and three having a single dominant mass surrounded by small satellite nodules. On nonenhanced CT images, the lesions were manifested as homogeneous masses of soft tissue attenuation, which was isoattenuated relative to normal muscle. On MRI, the lesions were isointense or slightly hypointense compared with that of normal muscle on T1-weighted images and hyperintense on T2-weighted images. After intravenous injection of contrast media, most of the masses (7/9) showed marked enhancement and slow washout with the degree of enhancement approaching that of the large arteries. And in the interior of four cases of larger masses (>5 cm) was observed fissured and radial patterns in both low-density area on CT and low-signal area on MRI. These patterns were pathologically proved to be fibrous. The pathological subtype of a sole disseminated case was plasma-cell type, where imaging findings showed a lining of well defined, sharply enhanced soft-tissue nodules in retroperitoneal zone.

Imaging findings of Castleman disease in the abdomen and pelvis are closely related to pathological type diagnosed. The characteristic features of localized and hyaline vascular type of Castleman disease include a solitary mass or a dominant mass surrounded with small satellite nodules, and high enhancement and slow washout with the degree of enhancement approaches that of large arteries. The presence of central areas of fibrosis of the larger tumors is one of the characteristic features of this disease.