What is a Rhabdomyoma?

A rhabdomyoma is a very rare kind of growth, or tumor, that develops from what is called striated muscle. Striated muscle is the main type of muscle in the body and consists of those muscles which are attached to bones — which can be used to move parts of the body at will — and the muscles of the heart. A rhabdomyoma is typically a benign tumor, meaning it is not cancerous, but could cause problems depending on the location in which it is growing. Most often, rhabdomyomas are found in adult men, in the area of the head or neck. Cardiac rhabdomyomas, which develop inside the heart, are more commonly found in babies.

In an adult, a rhabdomyoma generally appears in the form of a rounded lump, or lumps, most commonly situated in the neck. Usually, the tumor does not cause any problems until it grows large enough to press on surrounding structures, such as the throat or tongue. Symptoms might include swallowing and breathing difficulties or a hoarse voice.

What is called a fetal rhabdomyoma may affect infants in the first three years of life. The tumor is most likely to grow from striated muscle in the head or neck. Cardiac rhabdomyomas also tend to occur in children, developing while a baby is in the womb, and sometimes appearing on an ultrasound scan. They can be associated with a condition known as tuberous sclerosis, where growths occur in the brain, kidneys, lungs, eyes and skin, as well as the heart. Autism, epilepsy, learning difficulties and kidney problems can also be part of this condition.

Genital rhabdomyomas are found mostly in women, where they grow in the muscles of the vulva or vagina. Young or middle-aged women may be affected. As they are generally benign neoplasms, or non-cancerous growths, it is extremely unlikely for rhabdomyomas to become malignant, or cancerous, although in a few rare cases this has occurred.

The treatment of a rhabdomyoma depends on the type of tumor and the symptoms it is causing. In adults, a rhabdomyoma that causes breathing and swallowing difficulties requires surgical removal. Surgery may also be used to treat fetal and genital rhabdomyomas.

Management of cardiac rhabdomyomas is usually non-surgical, unless the tumor is large or in a position which prevents the heart from functioning. This is because most cardiac rhabdomyomas will shrink or sometimes even disappear completely. Non-surgical management involves monitoring the progress of the tumor and using drugs to regulate the rhythm of the heart if necessary. The outlook for a patient with a rhabdomyoma varies depending on where the tumor is located but is most often positive.