An unusual presentation of Castleman's disease.

Castleman's disease is one of the heterogeneous group of lymphoproliferative disorders of unknown aetiology. It commonly presents as a mediastinal mass. It can be unicentric involving only a single site, or multicentric involving multiple sites. We report a patient with unicentric Castleman's disease, in which the mass was located in the posterior mediastinum and accompanied by a massive pleural effusion, which is extremely rare in unicentric disease. This case report highlights the imaging techniques used in the differential diagnosis and surgical considerations due to the hypervascular nature of the tumour.