A TICKING TIMEBOMB: FLOATING AORTIC ARCH THROMBUS IN A PATIENT WITH METASTATIC SQUAMOUS CELL CARCINOMA OF THE LUNG

Abstract

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: Thoracic aortic mural thrombi are a rare clinical entity and most patients are asymptomatic before significant embolic events occur(1). There are only a few reported cases and are mostly in patients who presented with complications of peripheral thromboembolism. We report the case of a patient who presented with symptoms of congestive heart failure and was found to have a large floating thoracic aortic thrombus. CASE PRESENTATION: The patient is a 61-year-old female with no prior medical history who presented with shortness of breath on exertion and dry cough of three weeks duration. The patient has an extensive 40 pack-year smoking history. On evaluation, the patient was tachypneic, hypertensive, and was saturating well on room air. Crackles could be heard at the bases of the lungs and there was pitting edema of bilateral lower extremities. Laboratory studies showed a b-type natriuretic peptide level of 1741 pg/mL. A chest X-ray revealed pulmonary edema and bilateral pleural effusions. With a diagnosis of heart failure, gentle diuresis with intravenous furosemide was initiated. An echocardiogram showed global hypokinesis of the left ventricle with a reduced ejection fraction of 25-30%. CT scan of the chest revealed a large 6 x 7 cm necrotic mass in the left lower lung field with mediastinal adenopathy. There was a pulmonary embolus in the posterior basal segment of the left pulmonary artery, originating from the location of the mass. The CT was also significant for an intraluminal polypoid filling defect in the aortic arch with multiple small splenic and left renal infarcts, suggestive of a peripherally embolizing aortic thrombus. The patient was started on anticoagulation with low molecular weight heparin and was recommended to have an aortic arch stent placed to prevent further embolization of the thrombus. However, the patient decided against the procedure. Further biopsy and staging workup of the left lung mass revealed metastatic squamous cell carcinoma. The patient decided against palliative chemotherapy and opted for hospice care. DISCUSSION: Thoracic aortic mural thrombus is the result of disturbances in the Virchow's triad, ie, stasis, hypercoagulability, and endothelial dysfunction. The patient's smoking history, extensive atherosclerosis, malignancy, and left ventricular dysfunction were likely contributing factors. Aortic thrombi are prone to peripheral embolization to sites such as the spleen, kidneys, small bowel, and lower extremities(2). Early diagnosis and prompt management with anticoagulation are key. Endovascular repair with endograft stents is a novel modality of treatment with higher safety, patient acceptability, and a lower rate of peripheral embolization(3). CONCLUSIONS: Thoracic aortic thrombi are an initially silent rare disease condition with potentially fatal complications. Prompt management with anticoagulation and possible endovascular treatment is warranted. REFERENCE #1: Yang P, Li Y, Huang Y, Lu C, Liang W, Hu J. A giant floating thrombus in the ascending aorta: a case report. BMC Surg. 2020 Dec 9;20(1):321 REFERENCE #2: Bukharovich IF, Wever-Pinzon O, Shah A, Todd G, Chaudhry FA, Sherrid MV. Arterial Embolism Caused by Large Mobile Aortic Thrombus in the Absence of Atherosclerosis, Associated with Iron Deficiency Anemia. Echocardiogr Mt Kisco N. 2012 Mar;29(3):369–72. REFERENCE #3: Jamjoom R, Zagzoog MM, Sait S. Outcome of Endovascular Approach for Management of Thoracic Aortic Thrombus. Ann Vasc Surg. 2019 Aug 1;59:307.e7-307.e12. DISCLOSURES: No relevant relationships by Amjad Basheer, source=Web Response No relevant relationships by Rana Prathap Padappayil, source=Web Response No relevant relationships by DISHANT SHAH, source=Web Response No relevant relationships by vinit singh, source=Web Response No relevant relationships by Raghu Tiperneni, source=Web Response