Xanthoma is a skin condition in which fat builds up under the surface of the skin.

Skin growths - fatty; Xanthelasma

Xanthomas are common, particularly among older adults and people with high blood lipids.

Xanthomas vary in size. Some are very small, while others are bigger than 3 inches in diameter. They may appear anywhere on the body, but are most often seen on the elbows, joints, tendons, knees, hands, feet, or buttocks.

They may be a sign of a medical condition that involves an increase in blood lipids. Such conditions include:

• Certain cancers
• Diabetes
• Inherited metabolic disorders such as familial hypercholesterolemia
• Primary biliary cirrhosis

Xanthelasma palpebra, a common type of xanthoma that appears on the eyelids and may occur without any underlying medical condition, is not necessarily associated with elevated cholesterol or lipids.

A xanthoma looks like a sore or bump under the skin. It's usually flat, soft to the touch, and yellow in color. It has sharp, distinct edges.

Your health care provider will examine the skin. Usually, a diagnose of xanthoma can be made by looking at your skin. A biopsy of the growth will show a fatty deposit.

You may have blood tests done to check lipid levels, liver function, and for diabetes.

If you have a disease that causes increased blood lipids, treating the condition may help reduce the development of xanthomas.

If the growth bothers you, your doctor may remove it. However, xanthomas may come back after surgery.

The growth is non-cancerous and painless, but may be a sign of another medical condition.

The growth may cause a change in how you look. This is called cosmetic disfiguring.

Call your health care provider if xanthomas develop. They may indicate an underlying disorder that needs treatment.

Control of blood lipids, including triglycerides and cholesterol levels, may help to reduce development of xanthomas.

Errors in Metabolism. James WD, Berger TG, Elston DM, eds. Andrews' Diseases of the Skin: Clinical Dermatology. 10th ed. Philadelphia, Pa: Saunders Elsevier; 2005: chap 26.

Massengale WT, Nesbitt LT Jr. Xanthomas. In: Bolognia JL, Jorizzo JL, Rapini RP, eds.: Dermatology. 2nd ed. Philadelphia, Pa: Mosby Elsevier; 2008: chap 91.

Semenkovich CF. Disorders of Lipid Metabolism. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier. 2007: chap 217.