13th March 2024

Tumours of the Heart

Tumours of the Heart  

Aetiology

Cardiac tumours can be benign or malignant lesions, and either primary (originating within the heart) or secondary (metastatic spread from elsewhere). Primary cardiac tumours occur in roughly 1 in 3000 people, with the majority of lesions being benign (around 75%). Secondary tumours occur much more frequently, with around 10% of neoplasms believed to show evidence of cardiac metastases. They most commonly spread from intrathoracic cancers such as lung or breast, or from malignant melanomas.

Cardiac myxoma

By far, the most common primary tumour of the heart is the cardiac myxoma, making up a quarter of all cardiac tumours and over half of benign tumours. The majority of myxomas are found in the left atrium but can occur in any chamber. They are most often found in females between the ages of 40-60 years and usually present with symptoms of left/right heart failure. These lesions usually develop sporadically, but a small percentage (~10%) appear to be inherited and associated with an autosomal dominant syndrome called Carney Complex, which falls within the remit of multiple endocrine neoplasia syndrome. Patients with this condition tend to present with lesions at a younger age and with recurrent tumours developing in multiple areas of the heart at a time. Patients may also experience myxomas in other soft tissues, along with hyperpigmented skin lesions and endocrine tumours. 

Other benign lesions include papillary fibroelastoma, which accounts for three-quarters of cardiac tumours affecting the valves, rhabdomyomas and fibromas.

Sarcoma

Malignant tumours of the heart are most frequently sarcomas, making up 75% of all malignant lesions. Angiosarcomas make up 30% and tend to occur in middle-aged men. Typically, they originate within the right atrium and are composed of vascular structures. Rhabdomyosarcomas make up approximately 20% of malignant tumours and are the most common malignant cardiac tumours found in children. Other less-prevalent types of sarcomas include fibrosarcoma, osteosarcoma and myxoid sarcoma. 

Clinical manifestations

In many cases of cardiac tumours, the patient may have no symptoms at all and are often discovered during imaging for other conditions. When there are symptoms, the presentation depends on the size and location of the lesion. Some lesions grow large enough to impact on structures within the heart to obstruct function or blood flow. These patients may present with symptoms of heart failure, such as exertional dyspnoea, orthopnoea, and peripheral oedema. Myxomas have been described as creating an early diastolic tumour “plop” when large enough to prolapse through the atrioventricular valve. This is, however, an uncommon finding (around 15% of cases) and tumours more frequently present with a systolic murmur, loud first heart sound or an opening snap. Other symptoms include arrhythmias, palpitations, chest pain, finger clubbing and systemic features such as low-grade fever and weight loss. Cardiac lesions frequently result in embolic events due to fragmenting small parts of the tumour, or by forming a blood clot in the stagnant blood around it. Malignant tumours can invade nearby structures, which results in further complications such as pericardial effusion, cardiac tamponade, and superior vena cava syndrome.

Diagnostics

Since patients with cardiac tumours often present with non-specific symptoms, it is vitally important to exercise a high index of suspicion using a combination of history taking, clinical signs and imaging modalities. Chest x-ray and ECG may demonstrate evidence of atrial enlargement or arrhythmias. The recommended first-line investigation for a patient with concerning features of cardiac mass is echocardiography, with trans-oesophageal scans providing more detailed images. If a mass is discovered using this modality, further imaging may be required in the form of computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET) scan to provide additional diagnostic information and guide management. 

Image source: Wikimedia Commons (2017). UOTW 31 – Ultrasound of the Week 2, Licensed under a Creative Commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:UOTW_31_-_Ultrasound_of_the_Week_2.jpg (Accessed: 28 January 2024).

Management

Treatment of cardiac tumours will depend on the type, site, and size of the lesion, as well as the general health of the individual. Initial pharmacological treatments such as antihypertensives and antiarrhythmics can be used to stabilise the patient if there are symptoms of heart failure or arrhythmia, while the case is presented to a multidisciplinary team made up of oncologists, radiotherapists, and cardiac surgeons. In general, cardiac lesions require surgical excision, and this is often curative for benign lesions – although recurrence is possible. Surgical techniques include simple tumour resection, ex-situ resection and cardiac transplantation. The choice of technique will depend on the extent of the impact on surrounding structures, and whether other procedures, such as valve replacement are required. 

Malignant tumours often require systemic chemotherapy alongside surgery, and a substantial proportion have already metastasised at the time of detection. Secondary tumours have a poor prognosis and fail to respond to curative efforts.

References

• Atrial Myxoma. BMJ Best Practice. https://bestpractice.bmj.com/topics/en-gb/1054
• Cardiac Tumours. Patient. https://patient.info/doctor/cardiac-tumours
• Carney Complex. National Organisation for Rare Disorders. 2017. https://rarediseases.org/rare-diseases/carney-complex/
• Bussani R et al. Cardiac metastases. J Clin Pathol. 2007;60(1):27-34. doi:10.1136/jcp.2005.035105