Retroperitoneal Castleman's disease in the perinephric space--imaging appearance: a case report and a review of the literature.

INTRODUCTION Castleman's disease (CD) is a rare lymphoid tumour usually found in the mediastinum. Extrathoracic sites are uncommon. Its radiological findings may be similar to other retroperitoneal tumours, making diagnosis difficult. CLINICAL PICTURE A 54-year-old female was found to have an incidental hypoechoic mass in the left posterior perinephric space on routine ultrasound. Abdominal computed tomography (CT) scan demonstrated an isodense mass which enhanced brightly with intravenous contrast. Angiogram confirmed a hypervascular mass. TREATMENT The retroperitoneal mass was excised. OUTCOME Histology revealed CD of hyaline-vascular type. CONCLUSION CD should be considered in the differential diagnosis of a retroperitoneal mass, which demonstrates homogeneous and intense enhancement.