Castleman disease (CD) describes a group of three rare and poorly understood lymphoproliferative disorders that have heterogeneous clinical symptoms and common lymph node histopathological features. Unicentric CD (UCD) involves a single region of enlarged nodes. Multicentric CD (MCD) involves multiple regions of enlarged lymph nodes, constitutional symptoms, and organ dysfunction due to a cytokine storm often including interleukin 6. MCD is further divided into Human Herpes Virus-8 (HHV-8)-associated MCD, which occurs in immunocompromised individuals, and HHV-8-negative/idiopathic MCD (iMCD). Recently, iMCD has been further sub-divided into patients with TAFRO syndrome, which involves thrombocytopenia (T), anasarca (A), fevers (F), reticulin myelofibrosis (R), organomegaly (O), and normal or only slightly elevated immunoglobulin levels, and those who do not have TAFRO syndrome. Non-TAFRO iMCD patients typically have thrombocytosis, less severe fluid accumulation, and hypergammaglobulinemia. iMCD patients with TAFRO syndrome may have a worse prognosis, but more research is needed.