Cardiac tumors

Secondary (metastatic) tumors

Metastases affect the heart significantly more often than primary neoplasms. Several main patterns of tumor dissemination are distinguished:

• Direct extension (Direct extension): typical for intrathoracic tumors (lung cancer, mediastinal neoplasms). Direct invasion renders the tumor unresectable. Lung cancer can invade the atria via the pulmonary veins or venae cavae, making it critical to evaluate the atrial walls: if there is no invasion, resection is possible. Lymphoma can also invade the heart, which immediately changes the stage of the disease.
• Intralymphatic dissemination (Intralymphatic dissemination): typical for lung, esophageal, and breast cancer. Mesothelioma and adenocarcinomas frequently involve the pericardium, causing hemorrhagic effusion (a sign of late-stage disease).
• Haematogenous metastasis (Haematogenous metastasis): occurs in melanoma, leukemia, sarcoma, and systemic lymphomas.
• Intravascular dissemination (Intravascular dissemination): tumor thrombi spread transvenously. Renal, hepatic, and adrenal carcinomas extend via the inferior vena cava, while lung or thymic cancer extends via the superior vena cava.

CT is the method of choice for localization and staging, but has moderate accuracy in detecting direct invasion. Evaluating the border between the tumor and surrounding fat on CT is unreliable. MRI has the advantage here: the method allows visualization of the sliding motion between surfaces, which reliably excludes tissue infiltration.

Primary benign tumors

Primary neoplasms are rare, and the vast majority of them are benign. Clinical presentation depends on localization. Intracavitary tumors often have a pedunculated structure and can obstruct valves, causing obstruction, heart failure, and arrhythmias. On MRI (T1- and T2-weighted images), most tumors show isointense to hyperintense signals (exceptions include lipoma, fibroelastoma, and melanoma metastasis).

The most common types:

1. Myxoma (Cardiac Myxoma): the leading benign tumor (25%). More frequent in women. It can be asymptomatic or present with the classical triad: peripheral emboli, signs of mitral valve obstruction, and constitutional symptoms (anemia, fever, elevated ESR).
2. Rhabdomyoma (Rhabdomyoma): appears on echocardiography as a hyperechoic mass, typically attached to the basal portion of the interventricular septum.
3. Fibroelastoma (Fibroelastoma): on cine-MRI (SSFP cine sequences), these are mobile masses with low signal on valve leaflets, creating peritumoral turbulent flow.
4. Haemangioma (Haemangioma): often multiple masses within the ventricles. On CT/MRI, the structure is heterogeneous due to septa and calcifications, with intense contrast enhancement.
5. Hydatid disease (Hydatid Disease): parasitic cysts behave like benign tumors. These are well-circumscribed, loculated masses prone to calcification.

Primary malignant tumors

Practically all malignant primary neoplasms are sarcomas (ranking second after myxoma among all primary tumors) and lymphomas.

• Angiosarcoma (Angiosarcoma): the most common malignant tumor. Peak incidence occurs at 30–39 years of age, with a marked male predominance. It manifests with right heart failure, hemorrhagic effusion, and cardiac tamponade. It is almost always detected at advanced stages with metastases to the lungs, liver, brain, and bones.
• Lymphoma (Lymphoma): a rare aggressive B-cell tumor, usually seen in immunocompromised individuals. It affects the right atrium (without extracardiac foci). On MRI, it presents as multiple nodules or diffuse pericardial infiltration; on CT, it is isoattenuating to the myocardium.

Imaging criteria of malignancy:

• Size greater than 5 cm;
• Localization in the right atrium or involvement of multiple chambers;
• Broad base of attachment;
• Invasion into the mediastinum or great vessels;
• Hemorrhagic pericardial effusion;
• Heterogeneous delayed enhancement.

Role of the pericardium in diagnostic imaging

The pericardium is a fibro-serous sac that performs mechanical, membranous, and ligamentous functions. Normally, its cavity contains 15–30 ml of fluid. The thickness of the layers is 1.2 mm in diastole and 1.7 mm in systole (up to 4 mm is considered normal).

On CT and MRI, the pericardium is visualized due to the contrast between the fibrous tissue itself and the surrounding epicardial and mediastinal fat. On MRI using black-blood sequences, the pericardium appears as a thin hypointense line against a background of bright fat and fluid. Nodular pericardial thickening and hemorrhagic effusion are highly specific signs of metastatic involvement (e.g., in mesothelioma or malignant thymoma).

Class and exam questions

What else to study on this topic

• MRI signal characteristics in rare benign neoplasms (lipoma, fibroelastoma)
• Pathophysiology and imaging appearance of hemorrhagic pericardial effusion
• Echocardiographic differential diagnosis of valvular tumors and vegetations
• CT semiotics of intralymphatic and intravascular tumor dissemination

Other topics in the «Chest Radiology» section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.