Objective To explore the clinical,pathological,imaging characteristics,treatment,and prognosis of primary pericardial mesothelioma(PPM).Methods The clinical,pathological and imaging data of 11 PPM patients diagnosed in Peking Union Medical College Hospital from 2014 to 2024 were retrospectively collected,the Kaplan-Meier curve was calculated by Log-Rank test to determine the prognostic factors of the patients.Results The median age of the 11 patients was 48 years,including one well-differentiated papillary mesothelioma,and ten malignant mesothelioma.CA125 was elevated in all patients.PET/CT all indicated increased pericardial metabolism.Male patients and patients with ECOG score>2 points had worse prognosis(P=0.018,P=0.01,re?spectively).Compared with the untreated group(4 cases),both immunotherapy(3 cases)and chemotherapy(3 ca?ses)can prolong patient survival(P=0.025,P=0.025,respectively),and the benefit of immunotherapy was greater than chemotherapy(P=0.049 9).Conclusions This study is the largest single center pericardial mesothe?lioma cohort in China.CA125 and PET/CT contributes to the diagnosis of PPM,and immunotherapy might be the future direction of PPM treatment.

Objective To explore the diagnosis and treatment experience of malignant peritoneal mesothelioma by analyzing the clinical characteristics of patients with single center peritoneal mesothelioma.Methods Retrospec-tively analyze the clinical data,including age and treatment regimens,of 99 patients with malignant peritoneal mes-othelioma admitted to Peking Union Medical College Hospital from June 2012 to July 2023.Kaplan-Meier for surviv-al analysis and Logistic and Cox regression were applied to assess the impact of factors like age and treatment regi-mens on survival time.Results The median age of diagnosis for 99 patients with peritoneal mesothelioma was 56 years,of which 82 were pathologically diagnosed.Among them,38 cases(51.4%)underwent tumor cell reduction surgery,and 57 cases(77.0%)underwent systemic or local treatment.The median survival time for all patients was 43 years.The age of diagnosis may affect the prognosis of patients with malignant mesothelioma,and those aged≥65 at the time of diagnosis have a worse prognosis.Conclusions Malignant peritoneal mesothelioma is a rare but invasive malignant tumor with a poor prognosis.There is still a need to develop novo drugs and comprehensive treat-ment strategies.