Unicentric Castleman disease

Definition

A rare lymphoid hemopathy characterized by involvement of a single lymph node or a group of lymph nodes in one lymph node station (most commonly in the mediastinum, neck, abdomen, or retroperitoneum). Histopathologically, it may occur as a hyaline vascular subtype with hyaline-vascular follicles and a fibrotic and hypervascular stroma with sinus compression, or a mixed/plasmacytic subtype with dense, interfollicular sheets of (usually polytypic) plasma cells extending to the cortex, and variably sized lymphoid follicles including some with regressive changes. Clinically, most patients are asymptomatic, and lesions are detected incidentally.