Castleman disease is a heterogeneous nonmalignant lymphoproliferative disorder. Major distinctions include unicentric versus multicentric presentation; hyaline vascular, plasmacytic, or mixed pathology; and HHV8-associated (typically HIV-positive) versus idiopathic disease. At the NCCN 2019 Annual Congress: Hematologic Malignancies, Dr. Jeremy S. Abramson stated that rituximab is preferred as initial therapy for HHV8-positive disease, and chemotherapy can be added for patients with fulminant disease (antiretrovirals should always be used as well for those who are HIV-positive). Siltuximab is the preferred frontline therapy for idiopathic disease.