[Mediastinal angiofolicular lymphoid hyperplasia--Castleman's disease--case report].

Angiofolicular lymphoid hyperplasia was first described by Castleman as a lymph node hyperplasia characterized by abnormal follicles with small germinal centres and high capillary proliferation. The authors present a case of a 37 year old man with thoracalgy and a mediastinal mass of 4 cm diameter, fleshy and red with a white central area. The diagnosis of plasma cell type of angiofolicular lymphoid hyperplasia in an mediastinal lymph node was made. He also had involvement of two "diaphragmatic" lymph nodes. Angiofolicular lymphoid hyperplasia--Castleman's disease--is a rare lymphoproliferative disease that involves the mediastine or the pulmonary hilus when of solitary form but it can also have other localizations (multicentric or systemic form). Two histological variants are described, the hyaline vascular type and the plasma cell type. IL-6 seems to be in the plasma cell type, due to plasma cells proliferation. Castleman's Disease must be considered in the differential diagnosis of mediastinal masses, namely lymphomas.