C63-55 Two Roads to Shock: A Mediastinal Mass With Dual Hemodynamic Impact

Abstract T-cell lymphoblastic lymphoma (T-LBL) is an aggressive malignancy characterized by bone marrow biopsy showing 25% blasts and extranodal mass lesions. Compression of the pulmonary arteries (PA) is a relatively rare but recognized complication of anterior mediastinal masses such as T-LBL. However, it is uncommon for compression to reach hemodynamic significance. This case highlights the complexities of pulmonary hypertension and right heart failure in the setting of a relatively rare etiology. A 26-year-old female with a relevant history of hypothyroidism, type I diabetes mellitus, and recent COVID-19 infection presented as a transfer for evaluation of chest pain and dyspnea. Initial imaging with chest CT angiogram ruled out pulmonary embolism but identified a large 3cm pericardial effusion and flattened right ventricle consistent with tamponade physiology. Given medical history, initial differential diagnosis was viral verse autoimmune myocarditis. A pericardial window was performed, and shock ensued. Transthoracic echocardiogram showed an ejection fraction of 41-45%, a dilated right ventricle, and decreased RV systolic function. A subsequent right heart catheterization showed elevated right and left sided pressures with normal cardiac output and cardiac index. Initial imaging from the outside facility was re-reviewed with radiology who noted a large mediastinal mass compressing the PA. Biopsy of the mass demonstrated a T-cell neoplasm with extensive necrosis. Bone marrow biopsy showed normal cellularity given age, 1% blasts, and no evidence of marrow involvement. Lumbar puncture was negative for malignant cells. Intrathecal cytarabine was administered. Leuprolide acetate was initiated to protect fertility. Pre-phase treatment was started with bortezomib and prednisone followed by daunorubicin and bortezomib per the AALL1231 protocol. This case highlights the complex hemodynamic relationship in malignancy-associated obstructive shock, involving multiple mechanisms of circulatory compromise and the subsequent development of pulmonary hypertension. It is uncommon for the initial presentation of a mediastinal mass to be obstructive shock arising from two distinct sources. The increased afterload from the pulmonary artery obstruction temporized the tamponade physiology. However, after the tamponade was relieved, the patient developed worsening shock due to persistent PA obstruction. Extrinsic compression of the pulmonary artery causing RV failure, elevated pulmonary artery pressure, and normal wedge define group IV pulmonary hypertension, which this patient developed. Treatment would be best aimed at relieving the obstruction through surgical interventions or chemo/radiation therapy. This abstract is funded by: none