Cardiac Myxoma

Cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) myxoma is the most common of the primary tumors of the adult heart, all of which are very rare. Cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) myxoma is a benign Benign Fibroadenoma neoplasm that arises from primitive multipotent mesenchymal cells. Most occur sporadically, but some are a part of some familial syndromes. All 4 chambers may give rise to myxoma, but 90% originate and grow in the atria, with a left-to-right ratio of approximately 4:1. Diagnosis is made by echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA), cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) magnetic resonance imaging (MRI), or cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) computed tomography (CT). Complete surgical excision is required because of the substantial risk of embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding and cardiovascular complications, including sudden death.

Last updated: Jan 8, 2021

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Definition

Cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) myxoma is a benign Benign Fibroadenoma primary tumor Tumor Inflammation of the heart.

Epidemiology

Etiology

  • Arises from primitive multipotent mesenchymal cells 
  • No consistent genetic alterations in sporadic Sporadic Selective IgA Deficiency myxomas
  • Growth factors may contribute to tumor Tumor Inflammation formation, e.g., vascular endothelial growth factor Vascular endothelial growth factor A family of angiogenic proteins that are closely-related to vascular endothelial growth factor a. They play an important role in the growth and differentiation of vascular as well as lymphatic endothelial cells. Wound Healing (VEGF), an angiogenic factor.
  • Familial syndromes with myxomas are associated with specific genetic defects:
    • Carney complex: null mutations in PRKAR1A PRKAR1A Schwannoma, encoding a regulatory subunit of a cyclic-AMP–dependent protein kinase Protein kinase A family of enzymes that catalyze the conversion of ATP and a protein to adp and a phosphoprotein. Interferons
    • Mazabraud’s syndrome: single or multiple intramuscular myxomas with fibrous Fibrous Fibrocystic Change dysplasia Dysplasia Cellular Adaptation; activate mutations in the GNAS1 gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics

Pathophysiology

Anatomy and histology

Myxoma

Surgical gross pathology specimens (A, B, C, D, E) and histologic (F) findings of bilateral atrial myxomas
A: myxoma from left atrium
B: myxoma from right atrium
C: embolic myxoma from aortic bifurcation
D: embolic myxoma from left popliteal artery Popliteal Artery The continuation of the femoral artery coursing through the popliteal fossa; it divides into the anterior and posterior tibial arteries. Popliteal Fossa: Anatomy
E: embolic myxoma from right popliteal artery Popliteal Artery The continuation of the femoral artery coursing through the popliteal fossa; it divides into the anterior and posterior tibial arteries. Popliteal Fossa: Anatomy
F: histologic findings of myxoma (H&E (hematoxylin and eosin) x400): characteristic stellate tumor Tumor Inflammation cells within an abundant myxoid stroma

Image: “Myxoma” by Division of Cardiology, Department of Internal Medicine, College of Medicine, Hanyang University, Seungdong-Gu, Heangdang-Dong 17, 133-070 Seoul, South Korea. License: CC BY 4.0

Pathophysiologic mechanisms

  • Obstruction of blood flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure: causes heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
  • Interference with cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) valves: 
  • Embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding:
    • More common with small tumors (from fragments or surface thrombi)
    • More commonly systemic than pulmonic
  • Direct invasion of the myocardium Myocardium The muscle tissue of the heart. It is composed of striated, involuntary muscle cells connected to form the contractile pump to generate blood flow. Heart: Anatomy:
    • Left ventricular dysfunction
    • Arrhythmias/heart block
    • Pericardial effusion Pericardial effusion Fluid accumulation within the pericardium. Serous effusions are associated with pericardial diseases. Hemopericardium is associated with trauma. Lipid-containing effusion (chylopericardium) results from leakage of thoracic duct. Severe cases can lead to cardiac tamponade. Pericardial Effusion and Cardiac Tamponade
  • Invasion of the adjacent lung (can mimic lung cancer Lung cancer Lung cancer is the malignant transformation of lung tissue and the leading cause of cancer-related deaths. The majority of cases are associated with long-term smoking. The disease is generally classified histologically as either small cell lung cancer or non-small cell lung cancer. Symptoms include cough, dyspnea, weight loss, and chest discomfort. Lung Cancer)
  • Cytokine production (e.g., interleukin-6 Interleukin-6 A cytokine that stimulates the growth and differentiation of B-lymphocytes and is also a growth factor for hybridomas and plasmacytomas. It is produced by many different cells including T-lymphocytes; monocytes; and fibroblasts. Interleukins)

Clinical Presentation

Left-side myxomas (approximately 85%)

  • Symptoms similar to mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) or regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) (left heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)):
    • Dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
    • Orthopnea Orthopnea Pulmonary Edema
    • Paroxysmal nocturnal dyspnea Paroxysmal nocturnal dyspnea A disorder characterized by sudden attacks of respiratory distress in at rest patients with heart failure and pulmonary edema. It usually occurs at night after several hours of sleep in a reclining position. Patients awaken with a feeling of suffocation, coughing, a cold sweat, and tachycardia. When there is significant wheezing, it is called cardiac asthma. Pulmonary Edema
    • Cough/ hemoptysis Hemoptysis Hemoptysis is defined as the expectoration of blood originating in the lower respiratory tract. Hemoptysis is a consequence of another disease process and can be classified as either life threatening or non-life threatening. Hemoptysis can result in significant morbidity and mortality due to both drowning (reduced gas exchange as the lungs fill with blood) and hemorrhagic shock. Hemoptysis
    • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
    • Fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia
  • Neurologic symptoms: secondary to systemic emboli
  • Arrhythmias

Right-side myxomas (approximately 15%)

  • Symptoms of tricuspid disease (right heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)):
    • Fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia
    • Peripheral edema Peripheral edema Peripheral edema is the swelling of the lower extremities, namely, legs, feet, and ankles. Edema
    • Hepatomegaly
    • Ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites
    • Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope
    • Sudden death
  • Pulmonary embolism Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Pulmonary Embolism
  • If patent foramen ovale Patent Foramen Ovale A patent foramen ovale (PFO) is an abnormal communication between the atria that persists after birth. The condition results from incomplete closure of the foramen ovale. Small, isolated, and asymptomatic PFOs are a common incidental finding on echocardiography and require no treatment. Patent Foramen Ovale is present:

Constitutional symptoms Constitutional Symptoms Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis

  • May be seen in 30% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship 
  • Cytokine release Release Release of a virus from the host cell following virus assembly and maturation. Egress can occur by host cell lysis, exocytosis, or budding through the plasma membrane. Virology:
    • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
    • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery
    • Fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia

Diagnosis and Management

Physical examination

  • Left atrial tumors:
    • Diastolic “ tumor Tumor Inflammation plop” on auscultation
    • Pulmonary edema Pulmonary edema Pulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure. Pulmonary Edema: rales Rales Respiratory Syncytial Virus or crackles on auscultation
  • Right atrial tumors:
    • Diastolic murmur
    • Jugular venous distention
    • Generalized edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
    • Hepatomegaly
    • Abdominal ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites

Imaging

  • Echocardiography (usually 1st imaging technique):
    • Transesophageal echocardiography (TEE) gives better resolution.
    • Can usually identify:
      • Mass
      • Mobility
      • Obstruction
      • Embolization 
  • Cardiac magnetic resonance imaging (CMR): detailed anatomic imaging
  • Cardiac computed tomography (CCT): if CMR not available
  • Positron emission tomography (PET) scan helps differentiate:
    • Metastatic tumors versus atrial myxoma 
    • Lipomatous septal hypertrophy versus atrial myxoma
  • Coronary angiography: 
    • “Sea anemone” appearance on angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery
    • Mapping of blood supply: may be needed for surgical planning

Transvenous biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma

  • Risk of embolism
  • Should only be performed if diagnosis is uncertain and benefits outweigh the risks

Management

  • Surgical resection is required because of:
    • Risk of embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding
    • Cardiovascular complications
    • Risk of sudden death
  • Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas
    • Operative mortality rate Mortality rate Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status < 5%
    • Recurrence: 2%–5% of cases, more common if familial or multiple
    • Cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) autotransplantation (with atrial reconstruction) or transplantation may be necessary for recurrent atrial myxoma.
    • Atrial arrhythmias or atrioventricular conduction abnormalities in 26%
Gross pathology of excised left atrial myxoma

Gross pathology of excised left atrial myxoma, measuring 7 × 6 × 4 cm: Note the translucency of the tumor Tumor Inflammation, due to its abundant content of acid mucopolysaccharide ground substance Ground substance Connective Tissue: Histology.

Image: “Gross pathology” by Department of Neurology, Hospital of International University of Health and Welfare, 537-3 Iguchi, Nasushiobara, Tochigi 329-2763, Japan. License: CC BY 3.0

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Differential Diagnosis

Benign Benign Fibroadenoma primary cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) tumors or tumor-like masses

Malignant tumors of the heart

  • Sarcoma: malignant tumor Tumor Inflammation originating from the connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology cells. Exceedingly rare in the heart. Angiosarcoma is the most common type.  Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas is poor, as these tumors tend to grow rapidly and recur even when completely resected.
  • Metastatic tumors: 20 times more common than primary tumors. May be present in 20% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship dying of cancer. Symptoms depend on the site of cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) involvement. Diagnosis is made with echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA), CMR CMR Imaging of the Heart and Great Vessels, or CCT.

References

  1. Valvular Heart Disease. (2020). In Kumar, V., Abbas, A. K., Aster, J.C., (Eds.). Robbins & Cotran Pathologic Basis of Disease. (10th ed., p. 579).
  2. Gaasch, W.H., Salm, T.J.V. (2020). Cardiac tumors. UpToDate. Retrieved December 17, 2020, from https://www.uptodate.com/contents/cardiac-tumors?search=Atrial%20myxoma&source=search_result&selectedTitle=1~46&usage_type=default&display_rank=1#H12461347
  3. Kuon, E., Kreplin, M., Weiss, W., Dahm, J.B. (2004). The challenge presented by right atrial myxoma. Herz. 2004 Nov;29(7):702-9. doi: 10.1007/s00059-004-2571-7. PMID: 15580325.

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