Xanthomas are deposits of lipids in tissues, usually skin and tendons. These are often signs of dyslipidemia, which is a sign of inherited hyperlipidemia, often hypercholesterolemia. In other words, there are abnormalities of lipid amount or processing in the body and thus are important markers of underlying potential for heart disease and strokes. There are primary and secondary forms.
Xanthelasma is the most common form of xanthoma and manifests as yellow plaques along the upper and lower eyelids (see below). They start out as small bumps that slowly enlarge over several months to years. For many years they were believed to not be associated with hyperlipedemia, but more recently there have been reported associations with Type II hyperlipoproteinemia and primary biliary cirrhosis. To read more about Xanthelasma click HERE.
Primary Forms: Hypercholesterolemia, familial type, Combined dyslipdemia (Type III hyperlipoproteinemia), Hypertriglyceridemia (Type I, IV and V hyperlipoproteinemia) and Cerebrotendinoous xanthomatosis.
Eruptive Xanthomas (EX): EX are one of the more common cutaneous forms and manifest with sudden onset of small, yellowish orange to reddish brown papules that appear in crops over the entire body. The papules may be surrounded by an erythematous halo and may be grouped in various favored locations, such as buttocks, extensor surfaces of the arms and thighs, knees, inguinal and axillary folds, and oral mucosa. EX strongly suggest the possibility of elevated triglyceride levels. They may be associated with type 2 diabetes mellitus, chronic renal failure, hypothyroidism, and treatment with estrogens, coricosteroids or systemic retinoids. To read more about EV click HERE.
Tuberous Xanthomas (TS): Tuberous xanthomas are also referred to as Xanthoma Tuberosum. TX are found as flat or elevated and rounded, grouped, yellowish or orange nodules located over the joints, particularly on the elbows and knees. The lesions are indurated and tend to coalesce. They have been reported to involve the face, knuckles, toes joints, axillary and inguinal folds and buttocks. Solitary lesions have been found (see below). TS are most commonly associated with familial hypercholesterolemia but can also be found associated with Cerebrotendinous Xanthomatosis and Sitosterolemia. To read more about TS click HERE.
Additional forms include Xanthoma Planum (Plane Xanthomas), Palmar Xanthomas and Xanthoma Tendinosum (Tendon Xanthomas).
Secondary dyslipidemias associated with Xanthomas include:
- Diabetes Mellitus and insulin resistance
- Cholestatic liver disease, such as primary biliary cirrhosis
- Nephrotic Syndrome
- Oral retinoids
HISTOLOGY: The histologic features in all Xanthomas are similar, characterized by numerous large, xanthoma or foam cells, giant cells of the Touton type and clefts representing cholesterol and fatty acids. A common finding is connective tissue reactions around the nests of foam cells. In older lesions the foam cells are replaced with fibrosis.
TREATMENT: The importance of identifying Xanthoma disorders is in detecting and treating the underlying dyslipidemia, which may become life threatening. Xanthomas are an excellent example of cutaneous manifestations of systemic disease. Often with treatment of the underlying disorder the cutaneous manifestations improve, particularly with Eruptive Xanthomas. To read more about Xanthomas click HERE, HERE and HERE.