UNEXPECTED CAUSE OF POSTPARTUM CARDIAC ARREST: PRIMARY MEDIASTINAL LARGE B-CELL LYMPHOMA

Abstract

TOPIC: Disorders of the Mediastinum TYPE: Medical Student/Resident Case Reports INTRODUCTION: Lymphoma is the fourth most common malignancies in pregnancy, and a high portion is primary mediastinal (thymic) large B-cell lymphoma (PMBCL). It presents many challenges to diagnose lymphoma during pregnancy while avoiding fetal harm. CASE PRESENTATION: 41-year-old G2P1 female without significant past medical history experienced shortness of breath starting in her second trimester. She only had a telehealth appointment amid the COVID19 pandemic. The patient was offered a chest X-ray (CXR) but declined due to her concern of radiation. She was empirically managed as asthma triggered by acid reflux. At 39W of gestation, she presented to the hospital for labor and delivery. She was hypoxic and required three liters of oxygen. The physical exam was unremarkable. Lab were pertinent for mild leukocytosis and anemia. The patient still declined CXR. She was taken for C-section after failing trial of vacuum. The newborn was healthy. After delivering, she developed profound hypoxia in the OR requiring intubation. Tracheal compression was noted during intubation. CXR after intubation showed mediastinal widening. Following intubation, patient developed tachycardia, hypotension and ultimately cardiac arrest requiring CPR. Extracorporeal membrane oxygenation was activated. CT angiogram of the chest showed a 15 cm x 12 cm x 13 cm mass in the superior mediastinum that encases the aorta and great branches and was associated with direct extension into the sternum and invasion of the pericardium. The tumor also encased the trachea and left main bronchus. During her hospitalization, no neurological recovery was observed. The family decided to transition to comfort. The patient unfortunately passed away. The autopsy revealed neoplastic medium to large-size lymphoid cells in mediastinal mass, positive for CD45, CD20, BCL2, PAX-5, MUM-1, and MYC rearrangement negative for other markers. The final diagnosis was PMBCL. DISCUSSION: PMBCL is an aggressive B cell lymphoma arises from the thymus. Airway obstruction and superior vena cava syndrome are common due to local invasion. Dyspnea, B symptoms (fever, night sweats, weight loss) are possible symptoms. Labs may reveal elevated lactate dehydrogenase. Imaging studies typically illustrate an anterior mediastinal mass originating in the thymus. Final diagnosis can be made with biopsy and immunohistochemistry or flow cytometry analysis. Early recognition is important since these patients are at risk of cardiac and respiratory arrest during general anesthesia due to the mass location in the mediastinum. Pregnant patients should be informed that there is no evidence of fetal adverse outcome with imaging studies that expose the fetus to less than 50 mGy (CXR fetal dose: 0.0005 to 0.01 mGY). CONCLUSIONS: PMBCL should be identify early in pregnancy due to increased risk of cardiac and respiratory arrest. CXR is safe and harmless to the fetus. REFERENCE #1: Brenner B, Avivi I, Lishner M. Haematological cancers in pregnancy. Lancet. 2012;379(9815):580-587. REFERENCE #2: Dunleavy K, McLintock C. How I treat lymphoma in pregnancy. Blood. 2020 Nov 5;136(19):2118-2124. doi: 10.1182/blood.2019000961. PMID: 32797210. REFERENCE #3: Brent RL. The effect of embryonic and fetal exposure to x-ray, microwaves, and ultrasound: counseling the pregnant and nonpregnant patient about these risks. Semin Oncol. 1989 Oct;16(5):347-68. PMID: 2678486. DISCLOSURES: No relevant relationships by John Chronakas, source=Web Response No relevant relationships by Patrice Gillotti, source=Web Response No relevant relationships by Tien-Chan Hsieh, source=Web Response No relevant relationships by Oluwaseyi Olayinka, source=Web Response No relevant relationships by Nusrat Pathan, source=Web Response No relevant relationships by Akash Shah, source=Web Response No relevant relationships by Amanda Tissot, source=Web Response