What is Xanthoma?

Xanthomas are deposits of fats found in different parts of the body. While these fat deposits are harmless by themselves, they can often signal other underlying health issues. Early medical reports dating back to the 1900s first described these fat deposits and highlighted their connection to how the body processes fats.

Xanthomas have significance in a variety of medical fields, including general health, children’s health, skin conditions, and surgery. Current research shows a high level of interest in understanding why these deposits form and how they can be managed. Xanthomas can show up almost anywhere in the human body, but they are more commonly found in the skin or just beneath it. How these fat deposits behave and spread relates closely to the specific health issue causing them to form in the first place.

What Causes Xanthoma?

Not everyone who has high levels of cholesterol or fat in their blood, referred to as hyperlipidemia or hypercholesterolemia, will develop fatty, yellowish skin bumps known as xanthomas. However, these xanthoma bumps can be a noticeable sign that a person has these metabolic conditions.

Here’s what happens: in people with hyperlipidemia, fat-carrying particles in the blood can slip through the lining of blood vessels and get trapped in the skin, under-skin tissues, and tendons. Then, special cells in the tissue called macrophages eat up these fat deposits to clean up the area. This process forms the “foam cells” in xanthomas that are characteristic of the condition.

There’s another way a person could get xanthomas, even without high cholesterol. We think this happens when an area gets damaged, either by injury or inflammation. The damage makes blood vessels more leaky, and fat-carrying particles can leak out into the skin where they’re eaten by skin cells. This can cause what they call “eruptive xanthomas”, which is common in certain types of hypercholesterolemias. This is thought to be how people often get xanthomas on the Achilles tendon, an area that is frequently subjected to repeated mechanical stress.

Rarely, xanthomas can occur in a condition called paraproteinemia, which is when there are abnormal protein levels in the blood, including cases where the lipid levels are normal. In these patients, the xanthomas are thought to represent an overgrowth of lymph tissue in the skin that then develops into xanthomas.

Lastly, there’s a specific genetic condition called cerebrotendinous xanthomatosis, where xanthomas can occur in the brain and on tendons throughout the body, despite normal lipid levels in the blood. People suffering from this disease often have elevated blood cholesterol due to a genetic mutation.

Risk Factors and Frequency for Xanthoma

Xanthomas, which can occur at any age, usually start to appear during people’s teens if they have certain underlying health conditions such as familial hypercholesterolemia. This condition is seen in a large percentage (about 75%) of elderly people. A retrospective study of 5504 benign eyelid tumors seen in a Swiss eye department showed that around 6% were xanthelasma, which is a type of xanthoma. As xanthomas often come with different systemic diseases, their prevalence aligns closely with the prevalence of these conditions.

Signs and Symptoms of Xanthoma

Xanthomas are conditions related to skin or tendons that often bring patients into contact with various health care providers, including general practice doctors, dermatologists, general surgeons, orthopedic surgeons, and ophthalmologists. These patients often come seeking treatment for visible lesions, which can then be identified as symptoms of a related metabolic condition like familial hypercholesterolemia. It’s crucial for healthcare providers from different disciplines to be aware of these common lesions and their connections to systemic diseases.

Xanthomas show up on clinical exams as different types of lesions, including eruptive, tuberoeruptive, tuberous, tendinous, or planar.

Eruptive xanthomas: These are acute, inflamed lesions that show up rapidly as groups of pimples and then vanish after a few weeks.
Tuberoeruptive and tuberous xanthomas: These xanthomas are often associated with different states of hyperlipoproteinemia. They present as red, inflamed pimples that merge together. They tend to appear in specific body regions like the elbows or palms which can indicate certain types of hyperlipoproteinemia.
Tendinous xanthomas: These lesions generally develop slowly and are strongly linked with familial hypercholesterolemia. They often affect the Achilles tendons, elbows, and extensor tendons of the hand. Depending on whether the patient has a heterozygous or homozygous form of the disease, their prognosis can vary. For instance, Cerebrotendinous xanthomatosis is a form of this presentation and can show neurological signs such as corticospinal tract signs, cognitive decline, and gait difficulty.
Planar xanthomas: These xanthomas can be found on the palmar creases and flexure surfaces of fingers, skin folds and are typically seen with biliary cirrhosis. They could show up in different body parts and just by looking at them, healthcare providers can identify other systemic conditions that the patient may have. For instance, if planar xanthomas are found in the palmar crease, it could indicate familial dysbetalipoproteinemia type III.

Moreover, Xanthoma diabeticorum can be connected to severe diabetes and verrucous xanthoma is often seen along with histiocytes in connective tissues.

Testing for Xanthoma

When a patient first arrives with signs of xanthomas, which are fatty, cholesterol-filled deposits under your skin, doctors usually carry out an evaluation that focuses on both the local appearance of these fatty deposits, and any underlying disease that affects your entire body. An examination by a doctor is typically enough to diagnose this skin condition. Conventional X-rays usually don’t reveal anything in these patients. However, an ultrasound may be performed if the fatty deposits are found around the tendons. More advanced imaging methods like MRI scans might also be helpful, both for ruling out other potential causes of the fatty lumps and in planning any surgical procedures.

Once a diagnosis of xanthoma is made, doctors must also check for any underlying disease that could have caused it. This is crucial because it can help doctors identify deadly cholesterol-related conditions like familial hypercholesterolemia, which can cause heart disease at a young age.

To do this, the doctors will order a series of blood tests. These tests typically include checking the levels of different kinds of fats in your blood: plasma triglycerides, plasma cholesterol, serum low-density lipoproteins (LDL), and high-density lipoproteins (HDL). Generally, you would need to fast overnight before these blood tests, and other routine procedures might be needed according to the local laboratory’s rules. Specific patterns in the fatty deposit’s appearance, such as if they are diffusely flat and spread out, or found in the creases of your palm, could suggest other specific diseases associated with such skin changes. Tests for blood glucose and hemoglobin A1c, a form of hemoglobin that is chemically linked to glucose, might also be carried out to check for metabolic syndrome, a group of conditions that increase your risk of heart disease, stroke, and type 2 diabetes.

Treatment Options for Xanthoma

Xanthomas, which are yellowish nodules under the skin caused by accumulation of fat deposits, are primarily treated by addressing the medical conditions causing them. Sometimes, doctors may perform a surgical biopsy where the lesion is cut open and a sample is taken, to confirm the diagnosis or to provide relief if the xanthomas are causing discomfort. Identifying the specific type of lipid, or fat, in the xanthoma can help diagnose the underlying medical condition.

In cases where xanthomas form on areas like the Achilles tendon, which often rub against shoes or other surfaces, doctors usually excise, or remove, the entire lesion. This is done along with managing the underlying medical condition to reduce the chances of new lesions forming. Since wounds in the Achilles tendon area can be difficult to heal, it’s important to carefully manage soft tissues and use effective wound closure techniques.

In medical treatment, the main goal is to optimize the patient’s lipid, or fat, levels in the body. Medications like HMG-CoA reductase inhibitors have been successful in controlling high lipid levels and potentially reducing the size of xanthomas.

Interestingly, there have been reports of xanthomas decreasing in size naturally after procedures like liver transplants and plasmapheresis, a procedure where plasma is separated from the blood. This emphasizes the importance of managing the underlying medical condition as the principal treatment approach.

There are also newer treatment options being investigated, such as monoclonal antibodies that target specific proteins involved in cholesterol metabolism and a medication called 2-chlorodeoxyadenosine, particularly for extensive xanthomas (xanthoma disseminatum). These treatments have shown promising results in initial reports.

There have been few reports of uncommon cases where xanthomas, or fatty deposits, were caused by unusual accumulations of sterol. Examples of this include cerebrotendinous xanthomatosis which is an accumulation of a substance known as cholestanol and a condition called beta-sitosterolemia. In these cases, the patients also have a greater likelihood of developing atherosclerosis, a disease where plaque builds up inside your arteries. Because of this, it’s important that both the local symptoms and the larger, system-wide disease are carefully managed.

What to expect with Xanthoma

The overall health outcomes for patients with xanthomas, a condition where fatty growths develop under the skin, can vary greatly depending on several factors. The most crucial aspect to consider is the treatment of any underlying health issues, as xanthomas are often a symptom of an underlying condition rather than a disease in itself.

Some of these underlying conditions can be severe and incur early and high death rates, like homozygous familial hypocholesterolemia, an inherited condition that causes extremely high cholesterol levels. However, some conditions can be managed through changes in lifestyle and medication, which can significantly increase survival rates.

In terms of the xanthomas themselves, most smaller growths may decrease in size or even entirely disappear if the underlying condition is effectively managed. If the growths are large or in inconvenient locations, causing symptoms, a surgical approach might be needed. Recurrence after surgery can be limited with careful planning. However, trying to partially remove or reduce the size of these growths can lead to a very high recurrence rate. So, a careful assessment is essential before proceeding with any surgical intervention.

Possible Complications When Diagnosed with Xanthoma

: The treatment of xanthomas, which are fatty growths under the skin, may carry risks mostly associated with systemic therapy – which means the entire body is affected. An example of systemic therapy is using a type of drug known as HMG CoA reductase inhibitors. These drugs, commonly used, can have various side effects. These can be as minor as muscle aches, which affect up to 10% of users, to serious and rare conditions like rhabdomyolysis and necrotizing autoimmune myopathy, where the muscles can become damaged.

For people undergoing systemic therapy for xanthomas, it should be started and closely monitored by a healthcare provider who can promptly spot and manage any negative effects the medications may cause. Operations to remove xanthomatous growths could also come with complications. For instance, xanthomas that form on tendons often develop in places in the body prone to slow wound-healing. Therefore, surgeons need to plan carefully to reduce the risks of complications, like wound problems and growth regrowth.

Risks and Side Effects:

Medication side effects such as muscle aches
Uncommon but serious complications including rhabdomyolysis and necrotizing autoimmune myopathy
Complications from surgical removal of xanthomas
Delayed wound healing
Reoccurrence of xanthomas post-surgery

Preventing Xanthoma

People may visit a skin specialist or surgeon for a certain skin problem, not knowing that this problem is actually caused by a more complex health issue. That’s why it’s important to educate patients once they have been diagnosed. They need guidance on changes they should make in their day-to-day life, various treatment options, and the importance of regular check-ups in the future.

Keeping lipid and cholesterol levels in check can help prevent new similar skin problems in the same patient. Lipids and cholesterol are types of fat in your body, and if their levels are too high, they can cause health issues. Research has shown that the buildup of fatty deposits in arteries, a condition known as atheromatosis, often happens at the same time as the skin problem called xanthoma. This could lead to serious health problems and increase the risk of death or severe illness.