The following are summary points to remember from this pathological review of clinical and radiological effects of neoplasia and the heart:

1. Mechanisms of cardiac involvement in neoplastic disease include: direct mechanisms: i) Hematolymphoid metastasis: hematogenous seeding (e.g., melanoma, lymphoma), retrograde lymphatic seeding (e.g., breast carcinoma), and venous extension (e.g., renal carcinoma), ii) direct metastasis (e.g., lung carcinoma), iii) primary cardiac tumor growth, iv) intraluminal tumor growth; and indirect mechanisms: i) thoracic radiation, ii) chemotherapeutic agents, iii) carcinoid tumor (5-HT elaboration), and iv) plasma cell dyscrasia (amyloidosis).
2. Metastatic cancer: The incidence of metastatic disease to the heart is between 0.7% and 3.5% in the general population. Lung, breast, and hematological tumors and melanoma are among the malignancies that most frequently metastasize to the heart. Clinical presentation is often nonspecific and depends largely on tumor location and the extent of involvement. Pericardial metastases, responsible for >60% of cases of cardiac metastasis, result in signs and symptoms of pericarditis or effusion. Myocardial metastases account for about one-third of cases and can cause arrhythmia, chest pain, or other symptoms mimicking acute coronary syndrome. Endocardial involvement is rare (3%-5% of cases). Echocardiography is usually the first-line cardiac imaging for evaluation of potential masses because of its widespread availability. Cardiac magnetic resonance (CMR) is useful because of the ability to evaluate extracardiac involvement. Advantages of computed tomography (CT) include substantially higher spatial resolution, three-dimensional volumetric coverage, and better ability to visualize epicardial coronary arteries and mediastinal structures, which may help in planning surgery.
3. Primary cardiac neoplasms—benign: Primary cardiac neoplasms are rare—an incidence of 0.02%. The vast majority of these primary lesions are benign; however, catastrophic consequences may still occur, due to the sensitive location that these lesions may occupy. Benign lesions can obstruct flow, interfere with valve function, cause arrhythmia, and/or embolize (either the neoplasm itself or adherent thrombus), causing stroke or myocardial infarction. The most common primary tumors are primary fibroelastomas followed by myxomas. Other benign lesions include lipomas, lipomatous hypertrophy of atrial septum, hemangiomas, hamartomatous lesions (including pediatric tumors such as cardiac rhabdomyoma, cardiac fibroma, and the more rare hamartomatous lesions of cardiac myocytes).
4. Primary cardiac neoplasms—malignant: Undifferentiated high-grade pleomorphic sarcoma are the most common primary malignant neoplasm in the heart, including dated terms such as malignant fibrous histiocytoma and undifferentiated sarcoma. They usually (>80%) involve the left atrium, but tend to arise in the posterior wall, unlike myxomas, which arise on the atrial septum. Cardiac imaging is useful in staging, anticipating complications, and planning procedural interventions. Cardiac angiosarcoma is the most common primary cardiac malignancy exhibiting differentiation. They usually arise within the right atrium or right atrioventricular groove. Echocardiography is often used when these patients present with hemodynamic compromise owing to hemopericardium, leading to right-sided heart failure or tamponade. Primary pericardial mesothelioma is rare, yet it represents 50% of all pericardial tumors. The imaging features on CMR and CT overlap substantially with inflammatory pericarditis. Primary cardiac lymphoma accounts for 1%-2% of all cardiac neoplasms and preferentially involve the right cardiac chambers and the pericardium.
5. Secondary neoplastic effects of the heart include chemotherapeutic cardiotoxicity, cardiac amyloid, and carcinoid syndrome: Cardiotoxicity of certain classes of chemotherapies, such as anthracyclines (e.g., doxorubicin) and alkylating agents (e.g., cyclophosphamide) is well-known. Other agents, such as monoclonal antibodies (e.g., trastuzumab) and immune checkpoint inhibitors (e.g., pembrolizumab) are also increasingly recognized for their adverse effects on the heart. Cardiovascular radiation injury (pericardial injury, coronary artery disease, and valvulopathy) is most likely to occur after the treatment of malignancies close to the heart, such as breast, lung, and esophageal cancers, as well as thymoma and mediastinal lymphoma. Patients radiated for left breast cancer have been shown to have higher rates of apical perfusion defects. Esophageal cancer radiation may also cause similar defects in the inferior wall, owing to the different radiation port and relatively high doses. Approximately one-half of patients with AL amyloidosis, the product of an underlying plasma cell malignancy, will have cardiac involvement. CMR can be extremely useful in detecting signs of amyloid deposition. More than 50% of patients with carcinoid syndrome will develop carcinoid heart disease or carcinoid valvulopathy.

Keywords: Amyloidosis, Carcinoid Heart Disease, Balloon Valvuloplasty, Breast Neoplasms, Cardiotoxicity, Diagnostic Imaging, Echocardiography, Heart Failure, Hemangioma, Lung Neoplasms, Lymphangioma, Lymphoma, Non-Hodgkin, Magnetic Resonance Imaging, Melanoma, Malignant Carcinoid Syndrome, Neoplasm Metastasis, Neoplasms, Radiation, Radiology, Tomography, X-Ray Computed

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