Castleman disease (CD) describes a group of heterogeneous hematologic disorders with characteristic histopathological features. CD can present with unicentric (UCD) or multicentric (MCD) regions of lymph node enlargement. Some cases of MCD are caused by human herpesvirus-8 (HHV-8), whereas others are HHV-8-negative/idiopathic (iMCD). Treatment of iMCD is challenging, and outcomes can be poor. In this paper, we briefly report about symptoms of iMCD and about the International, evidencebased consensus diagnostic criteria for HHV-8-negative/idiopathic multicentric Castleman disease and International evidence based consensus treatment guidelines for idiopathic multicentric Castleman disease.