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Histologically, Castleman's disease associates three subtypes: 1-the vascular hyaline (HV) subtype more often seen in unicentric forms; 2-the plasmacytic (PV) subtype, more frequently associated with the HHV8+ and idiopathic multicentric form; 3-the mixed subtype associating both HV and PV aspects that may be encountered in any type of Castleman's disease. If the diagnosis of unicentric (isolated mass) and multicentric HHV8+ Castleman's disease is easy, the diagnosis of the idiopathic multicentric form remains particularly difficult because it is at the crossroads of many other pathologies (infectious, tumoral and dysimmune), making an anatomoclinical comparison necessary. The role of the pathologist, in the context of disseminated lesions (polyadenopathy and splenomegaly), is to identify lesions that may be part of Castleman's disease, to systematically perform HHV8 testing and to perform complete phenotyping associated with molecular analysis (B and T-cell clonality) in order to rule out a lymphomatous process and certain infectious etilogies. In all cases, its role will be a warning bell and the diagnosis of Castleman's disease will be retained only after a rigorous anatomic and clinical confrontation. © 2022 Published by Elsevier Masson SAS on behalf of Société nationale française de médecine interne (SNFMI).