Lymph Nodes, Castleman’s disease

Castleman’s disease is a rare lymphoproliferative disorder, which in itself is not malignant but may increase the risk of developing other malignancies. Histologically, Castleman’s disease may be classified as either the hyaline-vascular or plasma cell variant, with occasional cases demonstrating mixed features. It may be unicentric or multi-centric, and the hyaline-vascular histology accounts for most unicentric cases, with interleukin 6 (IL-6) playing a major role in its pathogenesis. Histopathologic features include: an increased proportion of follicular dendritic cells relative to lymphocytes within germinal centers, known as follicle regression; concentric arrangement of mantle zone lymphocytes in an "onion skin" pattern; and hypervascularity of follicles, some of which are radially penetrated by a hyalinized blood vessel, resembling a lollipop.