Relapsing B-cell lymphoblastic leukemia in an adult presenting as an infiltrative cardiac mass with tamponade.

We present a case of a 51-year-old man with a history of bone-marrow transplantation for acute lymphoblastic leukemia who returned 4 months later with cardiac tamponade. An echocardiogram showed a solid mass encasing the right ventricle (RV). Surgical biopsy of the mass revealed early relapse with lymphoblasts derived from B-cell precursors. We believe that this is the first description of relapsing B-cell acute lymphoblastic leukemia presenting as an intrathoracic mass with direct invasion of the adjacent cardiac structures causing tamponade physiology.