Conditions & Treatments

Pilomatrixoma

Pilomatrixoma is a slow-growing, hard mass found beneath the skin. It is most common on the face and neck, but is sometimes found elsewhere on the body.

Pilomatrixoma

What is pilomatrixoma?

Pilomatrixoma (also known as pilomatricoma) is a slow-growing, hard mass found beneath the skin. It is most common on the face and neck, but is sometimes found elsewhere on the body. Pilomatrixoma is usually a single lump, but, occasionally, multiple masses are seen. Most cases of pilomatrixoma are diagnosed in children, but the frequency in adults is now thought to be more common.

What causes pilomatrixoma?

Pilomatrixomas develop from an abnormal formation of cells that are similar to hair cells, which become hardened or calcified. The calcified cells form a mass beneath the skin.

Other members of a child's family may also have pilomatrixoma, suggesting a genetic component.

What are the symptoms of pilomatrixoma?

The following are the most common symptoms of pilomatrixoma. Symptoms may include:

  • A small, hard mass beneath the skin of the face, head, neck, or arms

  • The mass is usually less than 3 centimeters in diameter

  • The skin covering the mass appears normal, or it may feel firm or hardened

  • Usually, the mass is painless, unless it becomes infected

The symptoms of pilomatrixoma may look like other neck masses or medical problems. Always consult your child's health care provider for a diagnosis.

How is pilomatrixoma diagnosed?

Generally, pilomatrixoma is diagnosed by physical exam. Other tests may include a biopsy--a procedure in which tissue samples are removed (with a needle or during surgery) from the body for examination under a microscope to determine if cancer or other abnormal cells are present.

Treatment of pilomatrixoma

Treatment may include surgery to remove the mass and some of the surrounding tissue.

Treatment Programs


Massachusetts General Hospital understands that a variety of factors influence patients' health care decisions. That's just one reason why we're dedicated to ensuring patients understand their diagnosis and treatment options. Because a single option might not serve all patients, we offer a wide range of coordinated treatments and related services across the hospital. Patients should consult with their primary care doctor or other qualified health care provider for medical advice and diagnosis information.

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