An 68-year-old man with mucinous gastric adenocarcinoma presents with an embolic stroke. Echocardiography shows multiple small friable masses along the line of closure of the mitral valve. Histology confirms sterile platelet-fibrin vegetations. What is the underlying mechanism of this lesion?

• A Direct bacterial colonisation of damaged endothelium
• B Serotonin-mediated endocardial fibrosis restricting leaflet motion
• C Immune complex deposition activating complement on the valve surface
• D Hypercoagulability from tumour-derived mucins and tissue factor expression ✓

Explanation

Nonbacterial thrombotic (marantic) endocarditis consists of sterile platelet-fibrin vegetations arising on the line of closure of mitral or aortic leaflets in patients with adenocarcinomas or systemic hypercoagulable states. Mucin-secreting tumours and tumour tissue factor activity generate the prothrombotic state; the lesion presents with arterial emboli. Immune complexes describe Libman-Sacks endocarditis of lupus, and serotonin-driven fibrosis describes carcinoid heart disease, both distinct entities.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.