Xanthoma
Synonyms and keywords: Xanthoma, xanthomata, xanthomatosis

# Overview
A xanthoma (pl. xanthomas or xanthomata) (condition: xanthomatosis), from Greek xanthos, , "yellow", is a deposition of yellowish cholesterol-rich material in tendons or other body parts in various disease states. They are cutaneous manifestations of lipidosis in which there is an accumulation of lipids in large foam cells within the skin.
They are associated with hyperlipidemias, 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

# Causes

## Common causes of Xanthomas
- Hypercholesterolemia
- Hyperchylomicronemia
- Hyperlipidaemia
- Hyperlipoproteinemia

## Causes by Organ System

## Causes in Alphabetical Order
- Alagille syndrome
- Amyloidosis
- Apolipoprotein C-II deficiency
- Apoprotein E deficiency
- Cholestanol storage disease
- Chronic pancreatitis
- Familial hypercholesterolaemia
- Familial hyperlipoproteinemia type 1
- Familial hyperlipoproteinemia type 3
- Familial hypertriglyceridaemia
- Glycogen storage disease type I
- Hypercholesterolemia
- Hyperchylomicronemia
- Hyperlipidaemia
- Hyperlipoproteinemia
- Hypertriglyceridemia
- Hypothyroidism
- Juvenile xanthogranuloma
- Familial hypercholesterolaemia
- Myxedema
- Nephrotic syndrome
- Obesity
- Primary biliary cirrhosis
- Sitosterolemia
- Type Ia hyperlipoproteinemia
- Type Ib hyperlipoproteinemia
- Type Ic hyperlipoproteinemia
- Type IIa hyperlipoproteinemia
- Type IIb hyperlipoproteinemia
- Type III hyperlipoproteinemia
- Type IV hyperlipoproteinemia
- Type V hyperlipoproteinemia
- Vitamin E deficiency

# Types

## Xanthelasma
A xanthelasma is a sharply demarcated yellowish collection of cholesterol 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 papules 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 papules 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 papules and nodules that appear inflamed and tend to coalesce.  Tuberous xanthomas are considered similar, and within the same disease spectrum as tuberoeruptive xanthomas.

# Differential Diagnosis of Underlying Causes of Xanthoma
In alphabetical order.  
- Juvenile xanthogranuloma
- Nodular basal cell carcinoma
- Sebaceous hyperplasia
- Syringoma