Castleman Disease Presenting as a Mediastinal Mass.

Castleman disease is a complex benign lymphoproliferative disorder characterized by the enlargement of a single lymph node or a group of lymph nodes. Its etiology is unclear, with the mechanism of action of IL-6 and HHV-8 implicated as possibly associated with the development of the disease. Diagnosis depends on the histopathological findings of the involved lymph nodes. Surgical resection can be curative, but a small number of cases may be unresectable and need radiation and chemotherapy with subsequent resection if possible.