Retroperitoneal Castleman's disease with colon cancer. A rare association.

Castleman's disease (CD) is a rare disorder of uncertain aetiology characterised by massive proliferation of lymphoid tissue usually localised as mediastinal masses, although abdominal involvement has been reported. Localised forms are usually associated with a good prognosis, but several more aggressive multifocal variants have been observed. Two different histologic subtypes have been described: the hyaline vascular type, more common in unicentric CD and usually asymptomatic, and the plasma cell form. Unicentric CD may be associated with an increased risk of lymphoma, but there was no reported increased risk of other malignancies. A patient with plasma cell subtype unicentric CD localised in retroperitoneum associated with an adenocarcinoma of ileocaecal valve and liver metastasis is reported.