INTRODUCTION A 54-year-old female patient was transferred to our hospital because of progressive aggravation of chest tightness and suffocation for more than 1 month. ECG suggested an incomplete right bundle branch block. Cardiac ultrasound showed that the pericardial visceral layer was thickened unevenly and the echo was enhanced. The thickness of left ventricular apex was about 12mm, the left ventricular lateral wall was about 10mm, and the right ventricular lateral wall was about 11mm (Figure [1](#fig-cap-0001)). The pericardial visceral layer and the wall layer at the left ventricular lateral wall and the lateral posterior wall adhered to each other, resulting in reduced myocardial motion and the angle between left atrium and left ventricular posterior wall became smaller (Movie 1-2). Massive amount of hydropericardium can be seen in the pericardial cavity. The liquid depth of the right atrium is 20mm, the liquid depth of the right ventricular side wall is 22mm, and the band-like cellulose exudation can be seen between the right ventricular side wall and the pericardium (Movies 3). Tissue Doppler showed that the velocity e ‘of the mitral annulus on the ventricular septal side was 8.1cm/s, and the velocity e’ of the mitral annulus on the left ventricular lateral wall side was 3.5cm/s (Figure [2](#fig-cap-0002)-3). At the same time, a hypoechoic mass in the anterior mediastinum surrounding the ascending aorta and pulmonary artery can be scanned. Color Doppler flow imaging indicates that there is no blood flow signal inside the mass (Figure [4](#fig-cap-0003)-5). It is considered as a solid space occupying lesion in the mediastinum, with the exception of constrictive pericarditis caused by lymphoma pericardial infiltration, pericardial effusion (large amount), partial reduction of left ventricular wall motion and left ventricular diastolic function. PET-CT showed that there were irregular lumpy and flaky soft tissue density foci in the middle and upper mediastinum, which locally surrounded the blood vessels and trachea; The pericardium is unevenly thickened, the glucose metabolism is significantly increased (SUVmax 25.0), and the pericardium can see fluid density lesions. It is considered that this is the involvement of lymphoma as well (Figure [6](#fig-cap-0004)). Ultrasound in the neck suggested that the right supraclavicular lymph node was enlarged, and a lymph node puncture was performed to eventually diagnose primary mediastinal large B cell lymphoma (Figure 7-8). After one cycle of treatment with the first-line RCHOP regimen (metoclopramide 600mg D1, cyclophosphamide 1.16g D2, vincristine 2mg D2, pirarubicin 77mg D2, prednisone 100mg d2-6, q21d), the reexamination of cardiac ultrasound showed that the thickening of the pericardial viscera was less than before, the left ventricular wall motion of the lateral and posterior wall recovered significantly (Movie 4-5). Tissue Doppler showed that the velocity e ‘of the mitral annulus on the ventricular septal side was 7.8cm/s, the velocity e’ of the mitral annulus on the left ventricular side wall was 6.6cm/s(Figure [9](#fig-cap-0006)-10), and the pericardial effusion disappeared(Figure [11](#fig-cap-0007)).