What Is a Rhabdomyoma?

Cardiac rhabdomyoma is a rare cardiac tumor with skeletal muscle differentiation, second only to cardiac myxoma, the second most common benign cardiac tumor, and the most common primary in children. Heart tumors are more common, especially in newborns and infants. The literature reports that the prenatal detection rate is about 0.06%, and there is no obvious gender difference.

Basic Information

Visiting department

Oncology, Cardiac Surgery

Multiple groups

Newborns, infants

Common locations

heart

Common causes

May be derived from fetal heart myoblasts

Common symptoms

Heart murmur, arrhythmia, heart failure, and other accompanying symptoms

Causes of cardiac rhabdomyosarcoma

Cardiac rhabdomyosarcoma is considered to be a hamartoma of the myocardium rather than a real tumor. It may be derived from fetal cardiac myoblasts. Because many cases also have lesions such as nodular sclerosis of the brain, it is considered to be a tumor-like hyperplasia of the heart muscle. . One-third to one-half of children's primary cardiac rhabdomyosarcoma is associated with nodular sclerosis, which is a chromosomal dominant inheritance, which can be complicated by intra-brain hamartoma, facial sebaceous adenoma, and renal vascular smooth muscle lipoma. Recent scholars believe that cardiac rhabdomyomas may be caused by delayed or failure of apoptosis in part of the normal replication process of the heart.

Clinical manifestations of cardiac rhabdomyomas

Cardiac rhabdomyomas have various clinical manifestations, including cardiac murmurs, arrhythmias, heart failure, and other accompanying symptoms. These differences can be based on hemodynamic changes such as left or right heart blood flow obstruction, myocardial involvement, and heart rhythm disorders. To varying degrees.

The clinical manifestations of patients with cardiac rhabdomyomas depend on the tumor size, number, and location. Small tumors are generally asymptomatic. Larger tumors can block the heart cavity or valves and cause significant hemodynamic damage. Tricuspid valve obstruction can produce a right-to-left shunt of the oval foramen, and cyanosis can occur. Involving the conduction system can produce Severe arrhythmias, including complete atrioventricular block and ventricular tachycardia, which is difficult to control with drugs.

Specific clinical manifestations include arrhythmias (supraventricular or ventricular arrhythmias) and atrioventricular block; enlarged heart and valvular insufficiency (much like mitral stenosis, mitral valve atresia), aortic stenosis, and pulmonary valve Or subaortic stenosis, pericardial effusion, or even sudden death; non-specific manifestations include enlarged heart, left ventricular or right ventricular failure, and biventricular failure, systolic or diastolic murmurs, and sometimes bacterial endocarditis, Arterial embolism can occur and cause sudden death.

Cardiac rhabdomyosarcoma

Cardiac echocardiogram

Non-invasive, easy-to-use, low-cost, is a first-line diagnostic method for cardiac tumors. Rhabdomyomas are essentially solid tumors in the myocardium, invading many areas of the myocardium, with diameters ranging from a few millimeters to a few centimeters. Although different in size, they show the identity of echogenic light groups. Large rhabdomyomas can cause obstruction of the inflow or outflow tract of the left and right heart cavities, but no pericardial exudation has been reported.

2. Cardiovascular angiography

It can be shown that rhabdomyomas are multiple filling defects in the heart cavity, but the examination is expensive, and the main disadvantages of the need for multiple injections of contrast agent and catheter trauma are fewer applications.

3.MRI (magnetic resonance) examination

The non-invasive and multi-angle arbitrary cross-section imaging can accurately quantify and even qualitatively locate the mass, which has unique advantages.

4.CT scan

It is found that multiple nodular lesions from the atrioventricular septum, the CT value after enhancement is similar to the adjacent left ventricular muscle wall, with or without nodular sclerosis, and the possibility of cardiac rhabdomyomas should be considered first.

Cardiac rhabdomyosarcoma diagnosis

Imaging examination is of great significance for the diagnosis of cardiac rhabdomyomas. In recent years, advances in ultrasound diagnostic technology have significantly increased the detection rate of cardiac rhabdomyomas. If there is edema or arrhythmia during the fetal period, the diagnosis can be established by two-dimensional echocardiography; if there is severe congestive heart failure or ventricular tachycardia in the neonatal or infant period, the disease should be highly suspected and passed the ultrasound , Magnetic resonance, or computed tomography. For children with obstruction or arrhythmia, cardiac catheterization can obtain hemodynamic or electrophysiological data.

Cardiac rhabdomyosarcoma treatment

Cardiac rhabdomyomas tend to resolve spontaneously. Studies have found that tumors will stop growing or shrink in volume during the third trimester of pregnancy. In a small number of cases, there is still a trend of intrauterine growth. Cardiac rhabdomyomas in most children after birth will be in infancy. Partial or complete resolution, so conservative treatment is generally recommended. Drug therapy or surgical resection is necessary only when rhabdomyomas cause hemodynamic obstruction or heart rhythm disturbances that affect cardiac function.

The main goals of surgery are to remove hemodynamic obstructions, protect ventricular and valve functions, and prevent damage to the conduction system. Radical resection of the tumor is not necessary and dangerous. Intraluminal rhabdomyosarcoma with obvious symptoms has surgical indications, and age or whether it is accompanied by tuberous sclerosis is not a contraindication for surgery. Although rhabdomyosarcoma has no envelope, the boundary is clear, and surgery can be completely removed. Only when the tumor involves the main branch of the coronary artery, the annulus or the conduction system is difficult.

According to the tumor site, different surgical methods can be used. For right ventricular free wall lesions, a single vena cava cannula can be used to perform surgery without blocking the aorta. Double-cavity cannula can be used for ventricular septal or left ventricular lesions, and aorta can be blocked with moderate hypothermia. Deep hypothermia can also be used to stop circulation. The surgical incision should be selected according to the location of the tumor and strive for complete resection, but if it invades other important structures or multiple tumors, it cannot be removed reluctantly, only the obstruction part needs to be lifted. Tissue defects after tumor resection can be reconstructed with a patch.