A rare disorder of overgrowth (proliferation) of cells in the lymphatic system, also called giant lymph node hyperplasia and angiofollicular lymph node hyperplasia. It may lead to LYMPHOMA. The cell proliferation appears to be driven by one of the INTERLEUKINS and a MONOCLONAL ANTIBODY DRUG which produces an antibody to Interleukin-6 (siltuximab) is being trialled (2016) as treatment.