Non-infected vegetations: marantic, Libman–Sacks, carcinoid
- Lesion
Not every growth on a heart valve is an infection. Clots from sticky blood, lupus and tumour hormones also coat valves.
What it is
Valves can carry sterile vegetations. Nonbacterial thrombotic endocarditis (NBTE, marantic endocarditis) consists of small, bland fibrin-platelet thrombi along the lines of closure in hypercoagulable states, especially mucin-producing adenocarcinomas and sepsis; it embolises. Libman–Sacks endocarditis in systemic lupus erythematosus and antiphospholipid syndrome produces small vegetations on either or both sides of the leaflets. Carcinoid heart disease is plaque-like fibrosis of the right-sided valves and endocardium caused by serotonin and other products of carcinoid tumours that reach the heart, usually from liver metastases.
Structure
- NBTE: pink fibrin and platelet aggregates without neutrophils or organisms; valve underneath is usually normal.
- Carcinoid plaque: smooth-muscle cells and collagen in an acid mucopolysaccharide-rich matrix on top of the intact valve.
Vegetations compared
| Type | Size and look | Location | Key point |
|---|---|---|---|
| Infective endocarditis | Large, friable, destructive, with organisms | Any valve surface, often atrial side of AV valves | Fever, emboli, destroys valve |
| Rheumatic fever (acute) | Small, warty, along closure lines | Mitral and aortic | Followed by fibrosis and deformity |
| Nonbacterial thrombotic | Small, bland, sterile, loosely attached | Lines of closure | Cancer and hypercoagulable states; embolism |
| Libman–Sacks | Small to medium, sterile | Both surfaces of the leaflets, mitral and tricuspid | Lupus, antiphospholipid syndrome |
| Carcinoid heart disease | Pearly fibrous plaques, not true vegetations | Right-sided valves and endocardium | Serotonin from liver metastases |
Clinical notes
- NBTE can be the first sign of an occult cancer; recurrent embolic strokes are typical.
- Carcinoid heart disease causes right heart failure; flushing and diarrhoea point to the syndrome.
Test yourself
Think of the answer, then tap the question to see it.
Which tumours are classically associated with nonbacterial thrombotic endocarditis?
Mucin-producing adenocarcinomas, such as those of the pancreas and lung, through a cancer-associated hypercoagulable state.
Why does carcinoid heart disease mainly affect the right-sided valves?
The lung inactivates serotonin and related products, so the left heart is largely protected.
Where on the valve are Libman–Sacks vegetations found?
On either or both surfaces of the leaflets, mainly mitral and tricuspid.
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Endocarditis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025); Carcinoid syndrome: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.