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A3717 - Intravascular Lymphoma Mimicking Acute Pulmonary Embolism
Author Block: S. Cohen, M. Torossian, J. A. Falk; Pulmonary and Critical Care Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, United States.
Introduction: Intravascular lymphoma (IVL) is a rare condition where there is proliferation of clonal lymphocytes within small vessels. It most commonly affects the central nervous system and skin, but can infiltrate all organ systems. Presentation is non-specific and varies depending on which organ is involved. It has very high mortality and is usually diagnosed post-mortem.
Case Description: A 53 year-old previously healthy male presented with a three-week history of dry cough, dyspnea, fevers, night sweats, and malaise. Chest radiography showed bilateral patchy infiltrates. He was started on antibiotics for community acquired pneumonia and admitted to the hospital. Initial laboratory studies were unremarkable, including normal liver function tests. Despite antibiotics the patient became hypoxemic requiring increasing supplemental oxygen. Further workup revealed troponin 0.08 ng/mL, lactic acid 3.3 mmol/L, CD4 count of 294 cmm, negative HIV, and ferritin 3958 ng/mL. A transthoracic echocardiogram was notable for pulmonary artery pressure 65 mmHg. CT angiography of the chest was negative for pulmonary embolism. Several days into this hospitalization, the patient developed encephalopathy and demonstrated evidence of new severe liver injury with AST/ALT 420/450 U/L, total bilirubin 23 mg/dL, direct bilirubin of 16 mg/dL, and INR 1.4. Hepatitis serology and workup for autoimmune hepatitis was negative. Given his liver function was initially normal, it was thought that he had acute drug-induced liver injury. He was then transferred to our institution for evaluation for liver transplant. Shortly after arrival, the patient became obtunded and was intubated for hypoxemia due to inability to clear oropharyngeal secretions. Immediately following intubation, the patient developed shock requiring multiple vasopressors and refractory hypoxemia despite maximal ventilator support. He suffered cardiac arrest with pulseless electrical activity but survived cardiopulmonary resuscitation. A post-arrest echocardiogram revealed a severely dilated right ventricle with severely depressed systolic function. Unfortunately, the patient rapidly declined and expired despite resuscitative efforts. Autopsy revealed intravascular large B-cell lymphoma involving essentially all organ systems including the lungs, pulmonary arteries and capillary beds, heart, liver, brain, and kidneys.
Discussion: We believe IVL caused hypoxemic respiratory failure due to diffuse involvement of lymphoma in the pulmonary vasculature resulting in elevated pulmonary artery pressure and right ventricular dysfunction mimicking the clinical course of a massive pulmonary embolism. The suspected mechanism is similar to that in pulmonary tumor thrombotic microangiopathy, which is infrequently seen in solid organ cancers, though this is not well described in hematologic malignancies.