A rhabdomyoma is a

benign Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

striated muscle Striated muscle tissue is a muscle tissue that features repeating functional units called sarcomeres. Under the microscope, sarcomeres are visible along muscle fibers, giving a striated appearance to the tissue. The two types of striated muscle a ...

. Rhabdomyomas may be either cardiac or extracardiac (occurring outside the heart). Extracardiac forms of rhabdomyoma are sub-classified into three distinct types: adult type, fetal type, and genital type. Cardiac rhabdomyomas are the most common primary tumor of the heart in infants and children. It has an association with

tuberous sclerosis Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant genetic disease that causes non-cancerous tumours to grow in the brain and on other vital organs such as the kidneys, heart, liver, eyes, lungs and skin. A combinatio ...

. In those with tuberous sclerosis, the tumor may regress and disappear completely, or remain consistent in size. A common histological feature is the presence of spider cells, which are cardiac myocytes with enlarged glycogen vacuoles separated by eosinophilic strands, resembling the legs of a spider. It is most commonly associated with the

tongue The tongue is a Muscle, muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for chewing and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper s ...

, and

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

, but can also occur in other locations, such as the

vagina In mammals and other animals, the vagina (: vaginas or vaginae) is the elastic, muscular sex organ, reproductive organ of the female genital tract. In humans, it extends from the vulval vestibule to the cervix (neck of the uterus). The #Vag ...

Malignant Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

skeletal muscle tumors are referred to as

rhabdomyosarcoma Rhabdomyosarcoma (RMS) is a highly aggressive form of cancer that develops from mesenchymal cells that have failed to fully differentiate into myocytes of skeletal muscle. Cells of the neoplasm, tumor are identified as rhabdomyoblasts. The four ...

. Only rare cases of possible malignant change have been reported in fetal rhabdomyoma. The differential diagnosis in the tongue includes ectomesenchymal chondromyxoid tumor.

Cardiac Rhabdomyoma

It is much more common to find metastasis from an alternate site than a primary heart tumor. However, primary cardiac tumors do occur. One of these is the cardiac rhabdomyoma. Approximately 80-90% of these tumors are found in patients with

, a genetic condition causing multiple tumors, with most found prior to the age of one. Although these tumors are most commonly treated with resection, symptomatic tumors in fetuses have been shown to decrease in size after maternal sicrolimus administration. If clinically silent, they can be watched with routine imaging as the tumor will likely spontaneously regress.

Clinical Picture

The specific clinical picture of a patient with a cardiac rhabdomyoma is determined by its location in the heart. However, if symptomatic, most patients will present with

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...

or an

arrhythmia Arrhythmias, also known as cardiac arrhythmias, are irregularities in the cardiac cycle, heartbeat, including when it is too fast or too slow. Essentially, this is anything but normal sinus rhythm. A resting heart rate that is too fast – ab ...

such as

ventricular tachycardia Ventricular tachycardia (V-tach or VT) is a cardiovascular disorder in which fast heart rate occurs in the ventricles of the heart. Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple ...

heart block Heart block (HB) is a disorder in the heart's rhythm due to a fault in the natural pacemaker. This is caused by an obstruction – a block – in the electrical conduction system of the heart. Sometimes a disorder can be inherited. Despite the ...

. The severity of the symptoms will vary based on the size of the mass.

Detection

Cardiac rhabdomyomas are usually found in the ventricular walls or on the

valves of the heart A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart. A mammalian heart usually has four valves. Together, the valves determine the direction of blood flow through the heart. Hear ...

. With imaging techniques such as

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

and magnetic resonance imaging (MRI), these tumors are being detected with increased frequency and even in the prenatal period. Routine surveillance of children with tuberous sclerosis for cardiac rhabdomyoma or other cardiovascular manifestations of their disease may include electrocardiogram (EKG) and

echocardiography Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an ec ...

Additional images

Fetal intermediate cellular type rhabdomyoma

References

{{Tumors of lip, oral cavity and pharynx Benign neoplasms Heart neoplasia Oral neoplasia Pediatrics