Abstract 14694: An Uncommon Mass, in an Uncommon Location, in a Common Patient?

Abstract

Background: Myeloid sarcomas (MS) are rare extramedullary tumors composed of mature or immature myeloid cells. The heart is an uncommon site for this neoplasm. Case Presentation: A 68-year-old woman with a remote history of acute myeloid leukemia (AML) and allogeneic stem cell transplant presented with dyspnea. Her oxygen saturation was 70% on room air. Transthoracic echocardiography (TTE) revealed a nonhomogeneous intrapericardial mass measuring 6.3 cm by 10.0 cm, invading the right atrium and compressing the right ventricle (Figure 1). Due to persistent hypoxia, additional investigation with agitated saline contrast revealed a right-to-left intra-cardiac shunt. Cardiac magnetic resonance imaging showed invasion of the right and left ventricles, extension into the superior vena cava, and encasement of the right coronary artery. Due to worsening hypoxemia, vasopressin infusion and inhaled epoprostenol were initiated to reduce intracardiac shunting. Direct cardiac mass biopsy was considered prohibitive risk, however, a pericardiocentesis allowed for cytologic analysis of pericardial fluid which revealed atypical white blood cells, and subsequent flow cytometry indicated an aberrant myeloid population with monocytic features consistent with MS. She initiated chemotherapy with decitabine and low dose cytarabine. On day 6 of chemotherapy, she started external beam radiation therapy. A repeat TTE on day 10 of therapy showed a marked reduction in tumor size and intracardiac shunting. Discussion: MS can manifest before the development of bone marrow disease, following treatment for bone marrow disease, as relapse or progression of previous myelodysplastic or myeloproliferative neoplasms. With approximately fifty cases reported in the literature, most achieved temporary remission. Our approach to management included chemotherapy with decitabine and cytarabine and subsequent external-beam radiotherapy.