Snapshot Look at Castleman Disease

Castleman disease (CD) is a rare and heterogeneous group of lymphoproliferative disorders characterised by abnormal proliferation of lymphoid tissue. First described in the 1950s, it has since been classified into two major clinical forms: unicentric CD (UCD), involving a single lymph node region and multicentric CD (MCD), which affects multiple regions and is often systemic. Further subclassification of MCD includes HHV8‐associated MCD, POEMS‐associated MCD and idiopathic MCD (iMCD), each with distinct pathophysiologic mechanisms and clinical implications. This review summarises current understanding of the epidemiology, clinical presentation, histopathology, pathogenesis and diagnostic challenges of CD. It also explores recent advances in molecular biology, including the role of interleukin‐6 (IL‐6), human herpesvirus‐8 (HHV8) and aberrant immune signalling in disease progression. Therapeutic strategies vary significantly depending on the subtype and range from surgical resection in UCD to immunotherapy, siltuximab and cytotoxic chemotherapy in MCD. Despite progress, CD remains underdiagnosed and poorly understood, especially in its idiopathic forms. Continued research into its molecular underpinnings and targeted treatments is critical to improving patient outcomes and establishing evidence‐ based guidelines.