Heart of lymphoma: primary mediastinal large B-cell lymphoma with endomyocardial involvement

Abstract

Primary mediastinal B-cell lymphoma (PMBCL) is an uncommon aggressive subset of diffuse large B-cell lymphomas. Although PMBCL frequently spreads locally from the thymus into the pleura or pericardium, it rarely invades directly through the heart. Herein, we report a case of a young Mexican female diagnosed with PMBCL with clear infiltration of lymphoma through the cardiac wall and into the right atrium and tricuspid valve leading to tricuspid regurgitation. This was demonstrated by cardiac MRI and transthoracic echocardiogram. In addition, cardiac MRI and CT scan of the chest revealed the large mediastinal mass completely surrounding and eroding into the superior vena cava (SVC) wall causing a collar of stokes. The cardiac and SVC infiltration created a significant therapeutic challenge as lymphomas are very responsive to chemotherapy, and treatment could potentially lead to vascular wall rupture and hemorrhage. Despite the lack of conclusive data on chemotherapy-induced hemodynamic compromise in such scenarios, her progressive severe SVC syndrome and respiratory distress necessitated urgent intervention. In addition to the unique presentation of this rare lymphoma, our case report highlights the safety of R-CHOP treatment.

Figure 1

CT scan of the chest with contrast reveals a large lobulated anterior mediastinal solid mass (black arrow) with extension into the right hemithorax and the right atrium. There is displacement of the great vessels into the left hemithorax with significant mass effect on the right upper lobe. The tumor causes compression of the right pulmonary artery (red arrow) and right and left mainstem bronchi (white arrows).

Figure 2

Coronal CT scan image elucidates a mediastinal mass with extension into the right atrium (black arrow) with complete encasement and compression of the SVC. The tumor extends to the confluence of the IVC in the right atrium causing dilatation of the intraabdominal IVC and hepatic veins suggesting compromised cardiac return (red arrows). Tumor causes the displacement of great vessels into the left hemithorax.

Figure 3

A comprehensive 2 dimensional M-mode color flow and Doppler echocardiography reveals a normal left ventricular systolic function (EF 60–69%). A large right atrial mass measuring 5.8 × 4.7 cm almost fills the right atrium and extends into the tricuspid valve causing tricuspid regurgitation.

Figure 4

Cardiac MRI short axis T1 at the level of mitral valve reveals a large mediastinal mass infiltrating and obliterating the SVC causing SVC obstruction. The tumor extends into the right atrium (red arrow) and invades the tricuspid valve. Maximum diameter of the mediastinal mass measures 15 × 10 cm, and the mass in the right atrium measures 5.8 × 5.3 cm.