(682) Lung Cancer-Related Nonbacterial Thrombotic Endocarditis Presenting as Massive Acute Ischemic Stroke

Introduction: Non-bacterial thrombotic (marantic) endocarditis (NBTE) is a rare form of non-infectious endocarditis usually associated with advanced malignancy or connective tissue disorders. Thromboembolism in the presence of valvular vegetations with negative blood cultures may indicate NBTE and can be an initial presentation of cancer.
We present a rare case of acute hemispheric cerebral infarction due to NBTE secondary to lung adenocarcinoma.

Description: 49-yo woman presented with right sided weakness. She had history of tobacco use, a lung nodule and a recent lower limb deep venous thrombosis treated with apixaban.
CT angiography showed occluded M2 branch of left middle cerebral artery (MCA) for which she had mechanical thrombectomy (MT). Transthoracic echocardiogram was normal. Despite improvement of neurologic deficits after MT, she developed dense right hemiplegia 96 hours later. Repeat imaging showed multiple thrombi in multiple distal branches of the left MCA.
Transesophageal echocardiography confirmed a 7 mm mobile vegetation on the mitral valve. CT scans showed 1.7 cm spiculated mass in left upper lobe, distal pulmonary emboli and a left adrenal mass. CT guided biopsy of the lung nodule confirmed poorly differentiated adenocarcinoma. Blood cultures as well as serologies for Bartonella, Brucella, Coxiella burnetti, Leptospira and Francisella tularensis were negative. Anti-platelets and anticoagulation were continued. Thoracic surgical workup was initiated.
On day 8, she was intubated for loss of consciousness, left hemiplegia, anisocoria plus loss of corneal and cough reflexes at which time imaging (CT and MRI) demonstrated new right MCA occlusion with hemispheric infarction, uncal and trans-tentorial herniation.
She passed away after family opted to pursue comfort measures only.

Discussion: NBTE vegetations are strands of fibrin, platelets, mononuclear cells and immune complexes. Thromboembolism in cancer involves interplay of macrophages, monocytes and malignant cells releasing interleukins, tumor necrosis & tissue factors causing endothelial damage, platelet aggregation and thrombogenesis.
Our case shows that acute stroke in the presence of non-infectious heart valve vegetations necessitates a malignancy workup. Moreover, it illustrates the complexity of management of such patients.