Anna P. Olds, Craig Baker, and Jonathan Praeger
This chapter is a revision and update of that included in the previous editions of the TSRA Review written by Nicholas D. Andersen (2nd edition) and Joseph W. Turek (1st edition).
Background
Cardiac tumors are uncommon, with the majority being metastases. In decreasing order of frequency, the primary tumors sites include lung, breast, leukemia, lymphoma, esophageal, and melanoma. Primary cardiac tumor incidence is between 0.0017-0.19%. Of those with primary cardiac tumors, 75% are benign and 25% malignant.
Presentation
Patients with cardiac tumors can present with obstruction, embolization, arrhythmias, and nonspecific symptoms. Tumors in the atria or near the atrioventricular valves may mimic mitral or tricuspid stenosis by obstructing forward flow. When tumors infiltrate through the myocardium, heart failure symptoms, similar to various forms of cardiomyopathy, can result. In contrast to the constant symptoms seen with classic valvular stenosis, some cardiac tumors (i.e., myxomas) are pedunculated, causing a “ball-in-valve” type of obstruction resulting in paroxysmal symptoms, like dyspnea, depending on posture. Right atrial tumors can also invade or obstruct the SVC, causing SVC syndrome.
Many patients are diagnosed with cardiac tumors after suffering an embolic event from the tumor itself or associated thrombus. Embolic events can include strokes, pulmonary embolism, or peripheral emboli. Embolic events are more common in left sided tumors, with the brain being the most common location for embolization. Friable intracardiac lesions (i.e., papillary fibroelastomas and myxomas) have increased risk of embolic events.
Cardiac tumors can also cause arrhythmias from invasion of the myocardium and conduction system. Atrioventricular block is particularly common, especially from fibromas. Although rare, patients can even present with sudden cardiac death from a cardiac tumor. Patients with metastatic cardiac tumors from lymphoma or leukemia can present with nonspecific symptoms, like malaise, fevers, weight loss, etc. Malignant tumors of the heart are often associated with pericardial effusions, sometimes hemorrhagic.
Diagnosis
Often, cardiac tumors are found as part of a workup following an embolic event. Obstruction may be seen on chest x-ray as an enlarged cardiac silhouette, increased pulmonary vascular markings, pulmonary edema, or effusions. An EKG may show nonspecific arrhythmias. Transthoracic echocardiography is usually the first method of diagnosis. Transesophageal is preferred, as it can give more detail. Cardiac CT or MRI is used to evaluate tumor burden, wall penetration, and relation to other structures. Cardiac catheterization should be considered prior to surgical intervention when indicated per ACC guidelines to address coronary disease at the time of surgical intervention.
Types of Tumors
Metastases from other primaries
The majority of cardiac tumors are secondary metastatic tumors from other primaries. Lung, breast, leukemia, lymphoma, esophageal, melanoma, and sarcomas commonly metastasize to the heart or pericardium. Metastases spread hematogenously or via lymphatic channels from adjacent tissues in the chest, and multiple tumors are often present. Symptoms are uncommon, but patients can have pericardial effusions or tamponade. Surgery is generally directed at palliating symptoms of effusions via a pericardial window, either subxiphoid or into the left pleural space. Isolated cardiac metastases are rare, but could be resected. Surgical excision does play a role in certain subdiaphragmatic masses that have invaded the RA via the IVC, such as in aggressive renal cell carcinomas and neuroblastomas.
Benign
Adults
Myxomas are the most common primary cardiac tumors, comprising 50-70% of all primary cardiac tumors, and are more common in middle-aged women. Seventy-five percent of myxomas are in the left atrium and 18% in the right atrium, usually around the fossa ovalis. They grow on pedicles from the endocardium and can obstruct flow into the ventricle, or can take over the entire atrial cavity, mimicking mitral or tricuspid stenosis. They are gelatinous and usually coated with thrombus. Most sporadic myxomas are singular and have a low recurrence rate after resection. Carney syndrome is a familial syndrome with recurrent atrial myxomas, cutaneous myxomas, endocrine hyperfunction, and hyperpigmentation. Familial myxomas have a higher recurrence rate (12-20%). Intracardiac obstruction with CHF can lead to positional dyspnea (60-70%), emboli (30-50%), while some have constitutional symptoms (20%). Rarely, myxomas can obstruct ventricular outflow and mimic aortic and pulmonic stenosis, but many patients are asymptomatic. Surgical excision is indicated soon after discovery to prevent obstructive or embolic events, as these are potentially large and friable tumors. Recurrent myxomas should be excised as well.
Lipomas represent the second most common cardiac tumor in the adult population. They are encapsulated fatty tumors, often incidentally found anywhere in the heart, pericardium, or septum, often incidentally found anywhere in the heart, pericardium, or septum, most commonly in the right atrium. Lipomatous hypertrophy is a variant that affects the interatrial septum, is not encapsulated, and is more common than lipomas. MRI can usually establish the diagnosis. Surgical excision is indicated for lipomas and lipomatous hypertrophy only if symptoms are present, or if removal can be performed easily during a concomitant cardiac procedure. Most commonly, lipomas generate obstructive symptoms, whereas arrhythmias are more common with lipomatous hypertrophy.
Papillary fibroelastomas (endocardial papillomas) comprise 5% of primary cardiac tumors and are tumors of the valves or valvular endocardium, affecting all valves equally. They are white and gelatinous, about 1-2cm, resembling sea anemones, and may be associated with cytomegalovirus. Half are asymptomatic and incidentally found, while some present after embolic events, or obstruct coronary flow. Surgical resection is indicated upon diagnosis given the high rate of embolization. Valve repair with negative margins should be considered when possible.
Paragangliomas from chromaffin cells can produce catecholamines, particularly norepinephrine, but are usually not hormonally active. Hormonally active paragangliomas in the chest are referred to as hormonally active cardiac paragangliomas, with the term pheochromocytoma reserved for adrenal origin. Surgical resection is indicated. For hormonally active tumors, preanesthetic alpha and beta blockade as well as intraoperative and immediate postoperative monitoring is paramount.
Hemangiomas are rare vascular tumors presenting with arrhythmias, dyspnea, and heart failure symptoms. They can be diagnosed with angiography, and should be resected.
Mesotheliomas of the atrioventricular node are rare benign tumors and have been linked to sudden death due to heart block and ventricular fibrillation. Experience with excision is limited.
Children
Rhabdomyomas represent 40–60% of primary cardiac tumors in children, but are rare in adults, and are most commonly in the ventricles. They can be singular or multiple, are well circumscribed and non-encapsulated. Grossly, they appear gray. Most commonly, they present with heart failure symptoms from obstruction. Arrhythmias are also possible. They are thought to be hamartomas, and when present, are associated with tuberous sclerosis in more than 50%. Surgical excision is recommended before 1 year of age in patients without tuberous sclerosis. Given the poor long-term outlook, surgery in tuberous sclerosis patients is often palliative.
Eighty-three percent of fibromas occur in children, and they are overall the second most common benign primary cardiac tumor.They are solitary ventricular or ventricular septal tumors, nonencapsulated, firm, and nodular occasionally with calcium or bone deposits, sometimes making them identifiable on chest x-ray. Symptoms are from obstruction or arrhythmias. While complete surgical resection is curative if the tumor does not involve vital structures and can be enucleated, this is not always possible. Palliative tumor debulking does have a role with some patients surviving many years. Children with extensive fibromas have been managed with cardiac transplantation.
Malignant
Only 25% of primary cardiac tumors are malignant. Sarcomas make up 75% of these, including angiosarcoma (30%), rhabdomyosarcoma (20%), malignant mesothelioma (15%), and fibrosarcoma (10%). Lymphomas can also uncommonly be primary cardiac tumors and respond well to chemotherapy/radiation. Sarcomas can be in the right or left heart, or pulmonary arteries, and present with different symptoms as such.
Primary cardiac malignancies are usually sporadic in middle-aged or older adults with no family history, and are usually in the right atrium, but can be anywhere. They frequently present with heart failure symptoms, usually dyspnea, but can present with arrhythmias, effusions, etc.
They are extremely aggressive and survival without treatment is only several months. Complete surgical resection is the goal, but often challenging. Biopsy with subsequent neoadjuvant chemotherapy can help shrink tumors and make them more amenable to complete R0 resection, followed by post-surgical chemotherapy regardless of completeness of resection. Heart transplantation (autotransplantation or orthotopic) has also been used for treatment.
Surgical Pearls
Surgical resection of cardiac tumors should ideally achieve negative margins and be en bloc. Cardiopulmonary bypass should be initiated with bicaval cannulation if the tumor is atrial, and cardioplegia should be used to allow appropriate resection. Pulmonary vein vents should be avoided. Manipulation of the heart prior to cross-clamping should be minimized to prevent embolization of tumor or associated thrombus.
Left atrial tumors can be resected either with a minimally invasive or robotic-assisted approach. A lateral, longitudinal incision in the left atrium or biatrial incisions can provide good exposure. The atrial incisions can usually be closed primarily, but may require a patch. If there is a large defect in the atrial septum, consider a patch to avoid displacement of the tricuspid valve and subsequent tricuspid regurgitation. Ventricular tumors can be resected without full thickness excision of ventricular wall. Tumors from an AV valve can usually be resected without valve replacement, but the valve should be inspected.
To summarize, benign cardiac tumors should be resected, as this is usually curative and recurrence is rare. Malignant cardiac tumors, however, require preoperative assessment for metastatic disease, which would prevent resection. In the rare case where resection is possible for malignant cardiac tumors, surgery is usually palliative, and chemotherapy with or without radiation should also be used in many situations.
Suggested Readings
- Sabiston and Spencer Surgery of the Chest, 2016 edition, Chapter 103: Tumors of the Heart
- UpToDate: Cardiac tumors chapter
- Hoffmeier A, Sindermann JR, Scheld HH, and Martens S. 2014. Cardiac tumors—diagnosis and surgical treatment. Deutsches Ärzteblatt International, 111(12), p.205.
