Cardiac and pericardial neoplasms are relatively rare, affecting 1–3 per 10,000 patients. A review of 533 cases of primary heart tumours revealed that 60% were benign, 17% were pericardial and bronchogenic cysts and 23% were malignant primary tumours. An autopsy study in a total of 343 patients showed the frequency distribution of the most common benign and malignant primary cardiac tumours in both adults and children. The clinical course is often complicated due to cardiac arrhythmias and compromise of ventricular function due to mass effect or tamponade. Hence, histologically benign tumours can result in fatal outcomes if not adequately diagnosed and treated.
A relatively large review of primary cardiac neoplasms demonstrated approximately 10% mortality in myxomas, 30% mortality in non-myxoma benign tumors, and 100% mortality within 3 years in all patients with malignant tumors. Thus, pre-surgical diagnosis should focus on determining whether a tumor is benign or malignant, and more specifically whether a tumor is a myxoma or not.
More recently, modalities such as combined positron emission tomography (PET) and CT are being applied to assess tumors of the heart and pericardium. In the present review, the focus is on demonstrating the use of CT and MRI with relevant patient examples.
Magnetic resonance imaging
A study of 216 consecutive patients referred for cardiac MRI revealed tumors in 55, with 33 lesions histologically confirmed benign and 22 lesions malignant. Benign tumors could be predicted based on location (tumors in the left chambers were benign in 19/33 and malignant in 3/10) and based on tissue composition (50% of benign tumors were homogeneous vs 15% of malignant tumors), whereas signal intensity and contrast enhancement were not different between the two groups.
Other important predictors of malignancy included signs of myocardial infiltration, mass effect, pericardial and pleural effusions. MRI has proven extremely useful for assessment of pericardial disease, as it gives excellent tissue contrast and allows for clear visualization of the entire pericardial cavity.
The clinical utility of computed tomography for cardiac imaging increased dramatically with the introduction of ultrafast electron beam CT, which enabled high-resolution imaging of the heart and its chambers as well as cinematic imaging for assessment of cardiac function and even tumor motion. However, the recent developments with ECG-gated.
The clinical utility of computed tomography for cardiac imaging increased dramatically with the introduction of ultrafast electron beam CT, which enabled high-resolution imaging of the heart and its chambers as well as cinematic imaging for assessment of cardiac function and even tumor motion. However, the recent developments with ECG-gated multidetector row CT and dual source CT systems have led to another quantum leap in performance, enabling widely available clinical CT scanners to evaluate the heart with incredible detail. In order to give the reader some insight into the imaging findings of the most common cardiac and pericardiac neoplasms.
Benign cardiac neoplasms
This is the most common benign cardiac neoplasms, accounting for 50–60% of benign tumors as described in larger series. Symptoms range from asymptomatic coincidental detection in approximately 12% of subjects, to systemic embolic complications, dyspnea, palpitations and non-specific symptoms such as fatigue, weight loss or fever. Among patients with myxoma, 10% are inherited in autosomal dominant fashion. These patients tend to present at a younger age and have less female predominance compared to sporadic cases. Finally, familial myxoma more commonly occurs in the ventricular cavity and with multiple cardiac tumors in multiple locations.
This is by far the most common benign paediatric cardiac neoplasm, accounting for 90% of benign primary tumours. These lesions usually present within the first year of life, and up to 50% of patients have tuberous sclerosis. Most cardiac rhabdomyomas regress spontaneously, and surgical excision is only required in patients with life-threatening symptoms secondary to left ventricular outflow tract obstruction, arrhythmias or transient hypoxic spells.
These tumors may occur at any age and produce a characteristic tumor blush on arterial phase imaging, either using coronary angiography, CT or MRI. They may occur as part of the Kasabach–Merritt syndrome, but are more often incidental findings in asymptomatic patients.
Malignant cardiac neoplasms
Although these tumors are exceedingly rare in children, they represent the only primary cardiac malignancy in this age group. Typically, sarcomas are seen in adults, presenting around the 4th decade. The majority of these tumors are located in the right heart chambers, leading to right heart symptoms including cardiac tamponade with direct tumor extension into the pericardial sac. Angiosarcoma constitutes more than 1/3 of all cardiac sarcomas and has a predilection for the right atrium. Clinically, males are affected twice as often as females. These tumors tend to cause flow obstruction and heart failure. Hemorrhagic pericardial tamponade indicates tumor infiltration through the myocardium.
Malignant secondary cardiac tumors
Metastatic disease to the heart is much more common than primary cardiac malignancy. Cancers most likely to metastasize to the heart are described in Table. Melanoma is still a relatively rare tumor, although the incidence has been rising rapidly over the past decade. In 30–50% of melanoma patients, cardiac metastases will be found at autopsy. In absolute numbers, the most common cardiac metastases are caused by breast cancer and lung cancer. The latter gives rise to both direct pericardial invasion and metastases to the left cardiac chambers. Other cancers that frequently involve the heart include leukemia, lymphoma and esophageal cancer.
Although pericardial neoplastic disease remains relatively rare, they are more frequently identified than cardiac neoplasms. The initial clinical evaluation should focus on making the distinction between neoplastic and non-neoplastic causes for pericardial filling defects (such as cysts, hematomas or loculated effusions). Echocardiography is often the first imaging method, but both CT and MRI are capable of yielding important information for clinical management.
Pericardial neoplastic disease is much more frequently encountered than cardiac neoplasms. Most often, pericardial neoplasms arise from hematogenous or lymphatic metastatic spread or direct invasion of a non-pericardial primary malignancy, with lung cancer, breast cancer and melanoma most frequently encountered. The diagnosis is often made initially through echocardiography, but both CT and MRI have additional value in demonstrating the extent of the tumor and likely etiology. With future developments, it is quite likely that combined modality imaging, such as PET-CT or PET-MRI will gain greater applicability in the work-up of (peri-) cardiac neoplasms.