Castleman disease. Unusual retroperitoneal location indistinguishable from malignant tumor in preoperative angiographic appearance.

Castleman disease (angiofollicular lymph node hyperplasia) has been reported rarely as a solitary retroperitoneal mass radiographically indistinguishable from retroperitoneal malignancies. We report a case of a hyaline-vascular variant of Castleman disease presenting as a pararenal mass. The computerized tomographic and angiographic appearances of this lesion are presented, and the clinical importance of the differential diagnosis of retroperitoneal tumors is discussed.