Small skin lesions composed mainly of fat, xanthomas most often appear on the eyelid. Benign pseudotumors, they can however be a sign of a lipid disorder.

Xanthoma is a small lesion of the skin a few millimeters in size, usually yellowish in color. It is mainly made up of lipids (cholesterol and triglycerides).

There are different types of xanthoma depending on the affected area and the shape of the lesions. They are grouped under the term xanthomatosis:

• eyelid xanthoma, or xanthelasma, is the most common. It can affect the lower or upper eyelid, most often at the inner corner. It appears in the form of yellow patches or small balls of beige fat, corresponding to a deposit of cholesterol in the superficial layers of the skin;
• eruptive xanthoma is characterized by yellow papules appearing suddenly on the buttocks, elbows and knees. Sometimes painful, they disappear spontaneously but a transient pigmentation remains for some time;
• palmar striated xanthoma is found in the folds of the fingers and hands. More than a growth, it is more of a yellow spot;
• diffuse planar xanthomas affect the trunk and root of the limbs, sometimes the face, in the form of large yellowish patches. They are quite rare;
• tendon xanthoma affects the Achilles tendon or extensor tendons of the fingers not on the surface, but under the skin;
• Tuberous xanthoma mostly affects areas of pressure such as the elbows or knees. They vary in shape from small papules to firm lobular yellowish or orange tumors, often associated with an erythematous halo.

In most cases, a clinical examination by a dermatologist is sufficient to diagnose xanthoma. Rarely, a biopsy is done.

Xanthomas are mainly due to the infiltration under the skin of cells filled with lipid droplets composed mainly of cholesterol and sometimes triglycerides.

Xanthoma is often associated with a lipid disorder (hyperlipidemia). We then speak of dyslipidemic xanthomatosis. They are the witness of a primary familial or secondary hyperlipoproteinemia (diabetes, cirrhosis, medication, etc.), much more rarely of another dyslipidemia (cerebrotendinous xanthomatosis, sitosterolemia, Tangier disease). Faced with a xanthoma, it is therefore necessary to perform a complete lipid assessment with determination of total cholesterol, determination of HDL, LDL cholesterol, tryglycerides and apolipoproteins. 

Normolipidemic xanthomatosis, i.e. not associated with a lipid disorder, is very rare. They must seek different pathologies, especially hematological.

Only eyelid xanthoma (xanthemum) is not specifically associated with dyslipidemia.

The risks of xanthoma are those of the dyslipidemia with which they are associated. These are therefore cardiovascular risks.

Xanthomas can, for aesthetic reasons, be removed. If they are small, the dermatologist can remove them with a scalpel, under local anesthesia. If they are large or in the presence of a contraindication to surgery, the laser can be used.

If the xanthoma is associated with dyslipidemia, this should be managed with diet and / or treatment to avoid cardiovascular complications.