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# 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.

Updated Nov 12, 2026

## Key points

- NBTE: small, sterile, loosely attached thrombi without inflammation; cancer (Trousseau), sepsis, catheters; embolism is the danger.
- Libman–Sacks: mitral and tricuspid, both surfaces of the leaflets; can lead to fibrosis and regurgitation.
- Carcinoid heart disease: right-sided (tricuspid regurgitation, pulmonary stenosis) because the lung inactivates serotonin; liver metastases are needed for the syndrome.
- Carcinoid plaques sit on the surface of the valves and endocardium; they do not invade the valve.
- Similar left- or right-sided plaques occur with some serotonergic drugs (fenfluramine, ergot derivatives).

## 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](https://durgical.com/en/conditions/infective-endocarditis/) | Large, friable, destructive, with organisms | Any valve surface, often atrial side of AV valves | Fever, emboli, destroys valve |
| [Rheumatic fever (acute)](https://durgical.com/en/conditions/rheumatic-heart-disease/) | 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](https://durgical.com/en/conditions/systemic-lupus-erythematosus/) | 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.

## Memory aid

Big and wet with germs (infective), small and warty (rheumatic), small and lonely (marantic), both sides in lupus, and a right-sided coat from serotonin.

## 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.

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## Connections

## Related 6

- [Hypercoagulable states: inherited and acquired](https://durgical.com/en/general-pathology/hypercoagulable-states-inherited-and-acquired/)
- [Paraneoplastic syndromes: the table to know](https://durgical.com/en/general-pathology/paraneoplastic-syndromes-the-table-to-know/)
- [Infective endocarditis](https://durgical.com/en/general-pathology/infective-endocarditis/)
- [Rheumatic fever and rheumatic heart disease](https://durgical.com/en/general-pathology/rheumatic-fever-and-rheumatic-heart-disease/)
- [Gastrointestinal neuroendocrine (carcinoid) tumours](https://durgical.com/en/general-pathology/gastrointestinal-neuroendocrine-tumours/)
- [Systemic (arterial) thromboembolism](https://durgical.com/en/general-pathology/systemic-thromboembolism/)

## Related conditions 6

- [Systemic lupus erythematosus](https://durgical.com/en/conditions/systemic-lupus-erythematosus/)
- [Antiphospholipid syndrome](https://durgical.com/en/conditions/antiphospholipid-syndrome/)
- [Infective endocarditis](https://durgical.com/en/conditions/infective-endocarditis/)
- [Rheumatic heart disease](https://durgical.com/en/conditions/rheumatic-heart-disease/)
- [Pancreatic cancer](https://durgical.com/en/conditions/pancreatic-cancer/)
- [Tricuspid regurgitation and tricuspid valve disease](https://durgical.com/en/conditions/tricuspid-regurgitation-and-tricuspid-valve-disease/)

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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](https://medlineplus.gov/ency/article/001098.htm) (MedlinePlus, US National Library of Medicine, 2025); [Carcinoid syndrome: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000347.htm) (MedlinePlus, US National Library of Medicine, 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/non-infected-vegetations-marantic-libman-sacks-carcinoid/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/non-infected-vegetations-marantic-libman-sacks-carcinoid/