What are the other Names for this Condition? (Also known as/Synonyms)

• Tendon Xanthoma
• Xanthoma Tendinosum

What is Tendinous Xanthoma? (Definition/Background Information)

• Tendinous Xanthoma is the formation of firm lesions/nodules on skin mostly due to familial hypercholesterolemia, which is a rare inherited disorder causing increased blood (LDL) cholesterol levels
• The abnormal cutaneous lesions are known as xanthomas; while, the term ‘tendinous’ denotes that the lesions more often affect the tendons. Typically, the lesions form at the extremities, affecting the hands and feet
• Tendinous Xanthoma is observed in both children and adults. The lesions are usually benign and painless, but may grow to large sizes and be a cause for emotional stress
• In a majority of cases, treatment of the underlying inherited disorder through diet control, exercises, and prescription medications is undertaken. The xanthomas may be treated through surgery or laser therapy, if required
• The prognosis for Tendinous Xanthoma is good with suitable treatment of the underlying condition causing the subcutaneous nodules. However, there is a chance of recurrence following treatment

Who gets Tendinous Xanthoma? (Age and Sex Distribution)

• Tendinous Xanthoma is observed in both children and adults with an underlying genetic metabolic disorder such as familial hypercholesterolemia
• Both males and females may be affected
• Individuals of all racial and ethnic background may be affected. Worldwide, no geographical localization has been reported

What are the Risk Factors for Tendinous Xanthoma? (Predisposing Factors)

Factors that cause elevated LDL cholesterol levels can increase one’s risk for developing Tendinous Xanthoma, and these include:

• Familial hypercholesterolemia (FH) is a major risk factor
• Use of certain medications
• Poorly-controlled diabetes
• Hypothyroidism
• High-fat diet and lack of physical activities/exercise
• High BMI levels: Obesity or overweight conditions
• Excess consumption of alcohol

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Tendinous Xanthoma? (Etiology)

The cause of development of Tendinous Xanthoma is due to abnormal levels of low-density lipoprotein (LDL) cholesterol in blood.

• It may be described as the skin manifestation of inherited metabolic disorder such as familial hypercholesterolemia. It may be aggravated by the presence of diabetes or obesity
• When the metabolism of fat/lipid is affected, lipids in blood combine with certain proteins to form water-insoluble lipoproteins, which accumulate in macrophages beneath the skin to form xanthomas

What are the Signs and Symptoms of Tendinous Xanthoma?

The signs and symptoms of Tendinous Xanthoma may include:

• Presence of round to oval shaped papules or nodules below the skin, associated with tendons
• The nodules form on the limbs involving the tendons, ligaments, and bony tissue (periosteum)
• On the limbs, the xanthomas are noted on the back of the hands, over the elbows, and on the feet (including on the heel and Achilles tendon)
• The skin lesions are benign, but gradually increase in size over many months
• The nodules may have red-yellow discoloration
• In many cases, the lesions are about 1-2 cm in size, although larger nodules may be noted
• The lesions are usually painless and firm to touch

Additional signs and symptoms of the underlying/associated condition may be noted.

How is Tendinous Xanthoma Diagnosed?

A diagnosis of Tendinous Xanthoma may involve the following:

• A thorough medical history and physical examination
• Liver function test
• Lipid profile test
• Test for blood cholesterol levels
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Skin biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Note: A biopsy may be performed to rule out other skin conditions with similar signs and symptoms.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Tendinous Xanthoma?

The complications of Tendinous Xanthoma may include:

• The presence of large lesions may affect the quality of life and result in emotional/psychological stress
• Surgery to remove the tumors may give rise to scar formation on healing
• Formation of new lesions at other body sites, or recurrence of xanthomas after treatment
• Complications that arise from the underlying genetic/metabolic disorder

How is Tendinous Xanthoma Treated?

The primary treatment of Tendinous Xanthoma involves treating the underlying inherited metabolic disorder. The treatment measures may involve:

• Undertaking treatment for the underlying condition causing Tendinous Xanthoma through:
  • Appropriate diet and exercising
  • Weight control, for obese or overweight individuals; maintaining a healthy weight
  • Prescription oral or intravenously-administered medications
  • Undergo follow-up tests and checkups to ensure that lipid and cholesterol levels are controlled
  • Avoiding or minimizing alcohol intake; quitting smoking
• Treatment of skin lesions may involve (if necessary):
  • Application of trichloroacetic acid (TCA) for xanthelasma palpebrarum, seen on the eyelids
  • Laser therapy
  • Surgical excision and removal of large-sized tumors, if necessary

How can Tendinous Xanthoma be Prevented?

Currently, there are no known methods available to prevent the occurrence of Tendinous Xanthoma.

• If there is a family history of the underlying condition causing Tendinous Xanthoma, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders
• Having a low-fat diet and adequate physical activities/exercises to maintain optimal weight are beneficial in controlling blood lipid/cholesterol levels
• Oral medications to improve underlying hyperlipoproteinemia

Regular tests and periodic checkups to monitor the condition are recommended following treatment.

What is the Prognosis of Tendinous Xanthoma? (Outcomes/Resolutions)

• The prognosis of Tendinous Xanthoma is good with appropriate treatment of the underlying metabolic disorder. Even though the genetic metabolic disorder is incurable, the xanthomas are known to regress with appropriate therapy
• Inherited metabolic disorders, such as familial hypercholesterolemia, may increase the risk for cardiovascular diseases in the individuals to a great extent

Additional and Relevant Useful Information for Tendinous Xanthoma:

• Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition
• The presence of dirt on the body is not a causative factor for the condition. However, it helps to be clean and hygienic, which may help the condition from getting worse