Xanthoma
Encyclopedia
A xanthoma (condition: xanthomatosis), from Greek xanthos, ξανθος, "yellow", is a deposition of yellowish cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

-rich material in tendon
Tendon
A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments and fasciae as they are all made of collagen except that ligaments join one bone to another bone, and fasciae connect muscles to other...

s or other body parts in various disease states. They are cutaneous manifestations of lipidosis in which there is an accumulation of lipid
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...

s in large foam cells within the skin.
They are associated with hyperlipidemia
Hyperlipidemia
Hyperlipidemia, hyperlipoproteinemia, or hyperlipidaemia is the condition of abnormally elevated levels of any or all lipids and/or lipoproteins in the blood...

s, both primary and secondary types.

Tendon Xanthoma are associated with Type II hyperlipidaemia and chronic biliary obstruction.

Palmar xanthomata and tuboeruptive xanthomata (over knees and elbows) occur in Type III hyperlipidaemia

Xanthelasma

A xanthelasma
Xanthelasma
Xanthelasma is a sharply demarcated yellowish deposit of cholesterol underneath the skin, usually on or around the eyelids. Although not harmful or painful, these minor growths may be disfiguring and can be removed...

 is a sharply demarcated yellowish collection of cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

 underneath the skin, usually on or around the eyelids. Strictly, a xanthelasma is a distinct condition, only being called a xanthoma when becoming larger and nodular, assuming tumorous proportions. Still, it is often classified simply as a subtype of xanthoma.

Xanthoma tuberosum

Xanthoma tuberosum is characterized by xanthomas located over the joints.

Xanthoma tendinosum

Xanthoma tendinosum (also known as "Tendinous xanthoma") is clinically characterized by papule
Papule
A papule is a circumscribed, solid elevation of skin with no visible fluid, varying in size from a pinhead to 1 cm.With regard to the quote "...varying in size from a pinhead to 1cm," depending on which text is referenced, some authors state the cutoff between a papule and a plaque as 0.5cm,...

s and nodules found in the tendons of the hands.

Eruptive xanthoma

Eruptive xanthoma (ILDS E78.220) is clinically characterized by small, yellowish-orange to reddish-brown papule
Papule
A papule is a circumscribed, solid elevation of skin with no visible fluid, varying in size from a pinhead to 1 cm.With regard to the quote "...varying in size from a pinhead to 1cm," depending on which text is referenced, some authors state the cutoff between a papule and a plaque as 0.5cm,...

s that appear all over the body.

Xanthoma planum

Xanthoma planum (ILDS D76.370), also known as "Plane xanthoma", is clinically characterized by macules and plaques spread diffusely over large areas of the body.

Palmar xanthoma

Palmar xanthoma is clinically characterized by yellowish plaques that involve the palms and flexural surfaces of the fingers. Plane xanthomas are characterised by yellowish to orange, flat macules or slightly elevated plaques, often with a central white area which may be localised or generalised. They often arise in the skin folds, especially the palmar creases. They occur in hyperlipoproteinaemia type III and type IIA, and in association with biliary cirrhosis. The presence of palmar xanthomata, like the presence of tendinous xanthomata, is indicative of hypercholesterolaemia.

Tuberoeruptive xanthoma

Tuberoeruptive xanthoma (ILDS E78.210) is clinically characterized by red papule
Papule
A papule is a circumscribed, solid elevation of skin with no visible fluid, varying in size from a pinhead to 1 cm.With regard to the quote "...varying in size from a pinhead to 1cm," depending on which text is referenced, some authors state the cutoff between a papule and a plaque as 0.5cm,...

s and nodules that appear inflamed and tend to coalesce. Tuberous xanthomas are considered similar, and within the same disease spectrum as tuberoeruptive xanthomas.

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