Asymptomatic multicentric Castleman disease: a potential early stage of idiopathic MCD.

According to the diagnostic criteria for human herpesvirus 8 (HHV-8)-negative/idiopathic multicentric Castleman disease (iMCD) proposed by Castleman Disease Collaborative Network in 2017, there is a group of HHV-8-negative patients with multicentric Castleman disease (MCD) who do not have symptoms and hyperinflammatory state and do not meet the iMCD criteria. This retrospective study enrolled 114 such patients, described as asymptomatic MCD (aMCD), from 26 Chinese centers from 2000 to 2021. With a median follow-up time of 46.5 months (range, 4-279 months), 6 patients (5.3%) transformed to iMCD. The median time between a diagnosis of aMCD and iMCD in these 6 patients was 28.5 months (range, 3-60). During follow-up, 7 patients died; 3 of them died from progression of MCD. Despite that, 37.7% of patients received systemic treatment targeting MCD; this strategy was neither associated with a lower probability of iMCD transformation nor a lower death rate. The 5-year estimated survival of all patients with aMCD was 94.1% (95% confidence interval, 88.8-99.6). Transformation to iMCD was an important predictor of death (log-rank P = .01; 5-year estimated survival, 83.3%). This study suggests that patients with aMCD may represent a potential early stage of iMCD, who may not require immediate treatment but should be closely monitored.