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Therapeutics in Dermatology
A reference textbook in dermatology

Xanthomas et xanthomatoses

24 October 2012, by ADAMSKI H.

Xanthomatoses are conditions characterised by the appearance of yellowish skin deposits, referred to as xanthomas, essentially consisting of cells filled with fats (lipids made up of cholesterol and triglycerides).

The appearances of xanthomas vary as a function of where they occur. The lesions may not always appear yellow. Xanthomas may be indicative of a disease that affects the body as a whole related to increased blood lipid levels (hyperlipidemia) caused by the abnormal elevation of cholesterol (hypercholesterolemia) and/or triglycerides (hypertriglyceridemia).

1 - DIFFERENT TYPES OF XANTHOMAS

1.1 - XANTHELASMA OR PALPEBRAL XANTHOMAS

Xanthelesma is the most common form of xanthomas. The lesions are soft and occur in the corner of the upper and lower eyelids and they may merge to form yellowish plaques. Only half the patients presenting with xanthelasma also present with hyperlipidemia that is most often related to an increase in blood cholesterol levels.

1.2 - PALMAR STRIATED XANTHOMA

In palmar striated xanthoma, yellow, linear lesions are visible in the creases of the palms and fingers. The condition is often associated with blood lipid disorders.

1.3 - DIFFUSE PLANAR XANTHOMA

Planar xanthomas are characterised by yellowish lesions that often occur in plaques on the torso and at the base of the limbs. In most cases, they are associated with blood diseases with patients presenting with abnormal amounts of paraproteins called immunoglobulins.

1.4 - ERUPTIVE XANTHOMA

Eruptive xanthoma is characterised by small, yellowish-brown lesions a few millimetres in diameter that appear suddenly and most often on the buttocks, elbows and knees. The lesions may sometimes be painful and then disappear, leaving the skin transiently pigmented. The lesions are almost always associated with hypertriglyceridemia (abnormally high blood triglyceride levels).

1.5 - TUBEROUS XANTHOMA

Tuberous xanthoma is characterised by big, red, nodular lesions measuring up to several centimetres. The lesions usually occur in pressure areas (elbows, knees, buttocks). They are observed in patients presenting with hypertriglyceridemia and/or hypercholesterolemia.

1.6 - TENDINOUS XANTHOMA

Tendinous xanthoma is characterised by deep-lying lesions, most commonly in the Achilles tendon and the extensor tendons of the fingers. The skin covering the nodules is normal in colour. The nodules are mobile under the skin and painless. They are often a symptom of familial hypercholesterolemia.

2 - DIAGNOSIS

Xanthomas are generally easily diagnosed by dermatologists. Should the dermatologist have any doubts, a small piece of the lesion is removed (skin biopsy) and sent to a laboratory specialised in pathological anatomy to confirm the diagnosis. The detection of xanthomas may result in tests being carried out to check whether the xanthomas have spread throughout the body (xanthomatosis).

Patients must be tested for blood lipid disorders (hyperlipidemia). Lipids (triglycerides and cholesterol) are transported in the blood by lipoproteins. Patients need to be fasting for the blood test. The assessment includes the assay of total cholesterol, triglycerides and HDL-cholesterol, referred to as “good cholesterol”. The main role of HDL is to remove excess cholesterol from the cells. It is also important to calculate LDL-cholesterol levels. LDL-cholesterol is considered to be “bad cholesterol” because it gets deposited in artery walls (atheroma), producing cardiovascular disease (infarction, stroke, etc.). Lipoprotein ultracentrifugation may also be requested to complete the assessment. Lipoproteins are heterogeneous particles that can be isolated by ultracentrifugation based on density. There are five major classes of lipoproteins: chylomicrons, VLDLs (very low density lipoproteins), LDLs (low density lipoproteins), IDLs (intermediate density lipoproteins) and HDLs (high density lipoproteins).

3 - CAUSES

Xanthomatoses have been divided into two types:

– Xanthomatoses associated with blood lipid disorders (hyperlipidemia)

  • Of familial origin. These xanthomatoses are classified according to Frederickson’s classification which distinguishes 5 types and 2 subtypes of hereditary hyperlipidemias (I, IIa, IIb, III, IV, V) as a function of the lipoproteins (chylomicrons, VLDL, LDL, IDL and HDL) which are the most elevated in the blood of patients.
    • type I: chylomicron and triglyceride are increased. The serum appears creamy
    • type II subdivided into: subtype IIa or pure hypercholesterolemia (only LDL levels are increased); and subtype llb or mixed hypercholesterolemia (both LDL and VLDL levels are increased);
    • type III: triglyceride and cholesterol levels are increased as are VLDL and IDL levels. The serum appears turbid;
    • type IV: the blood is creamy and has high triglyceride and VLDL levels. The serum is turbid;
    • type V: this form is associated with elevated chylomicron, triglyceride and VLDL levels. The serum is creamy. This type is a combination of types I and IV. 
  • Or that may arise with diseases such as diabetes, chronic renal failure and cirrhosis, or with excessive alcohol intake or following treatment with certain medicines (oestrogen-based contraceptives, corticosteroids).

– Xanthomatoses not associated with blood lipid disorders, which are very uncommon. Patients need to be tested for xanthomas in the body and for blood disorders (presence of large amounts of immunoglobulins in the blood).

4 - TREATMENT

If the xanthoma is caused by a blood lipid disorder, management is based on treatment of the lipid disorder, aiming to restore blood lipids to normal levels.

Xanthomas do not require removal unless they are aesthetically embarrassing (xanthomas of the eyelids for example), or large (tuberous or tendinous xanthomas). Several techniques may be used and should be discussed as a function of the size and localisation of the xanthoma. Curettage is only used for small lesions. Xanthoma lesions of the eyelids or deep-lying tuberous or tendinous lesions may be removed by surgical excision. Laser treatment has been found to be useful.

In patients with blood lipid disorders, treatment aims to normalise the levels of cholesterol and triglycerides in the blood and to prevent cardiovascular complications. As blood lipid disorders are intrinsic, treatment has to be long-term and instituted for life. Management of blood lipid disorders is based on lifestyle and eating habit changes (reducing calorie intake in obese patients, following a low-fat diet), to be adapted according to the disease and supplemented, if required, by administration of medicinal products to lower cholesterol and/or triglyceride levels.

5 - SYNONYMS

Xanthoma, xanthelasma, xanthomatosis; planar xanthoma, necrobiotic xanthogranuloma, juvenile xanthogranuloma, papular xanthoma, verruciform xanthoma. 

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