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Xanthoma Tendinous Plaques – A Complete Guide

What is Xanthoma tendinous plaques?

Xanthoma tendinous plaques are yellow‑orange, raised, often buttery‑soft deposits that develop on the surface of tendons, most commonly the Achilles tendon, extensor tendons of the hands, and the patellar tendon. They are composed of lipid‑laden macrophages (foam cells) that accumulate within the connective tissue. While they are usually benign and painless, their presence frequently signals an underlying disorder of lipid metabolism.

In dermatology, “xanthoma” refers to any lipid‑rich lesion of the skin or subcutaneous tissue. When the lesion forms within a tendon sheath, it is called a tendon xanthoma or tendinous xanthoma plaque. The plaques can feel firm or rubbery, range from a few millimetres to several centimetres, and may be multiple.

Common Causes

Most tendinous xanthomas arise from chronic elevations of low‑density‑lipoprotein (LDL) cholesterol. The following conditions are the most frequently implicated:

• Familial hypercholesterolemia (FH) – an autosomal‑dominant disorder causing very high LDL from birth.
• Familial combined hyperlipidemia – elevated LDL and triglycerides with variable patterns.
• Type IIa hyperlipoproteinemia – isolated LDL excess.
• Type III hyperlipoproteinemia (dysbetalipoproteinemia) – accumulation of remnant particles, often with palmar xanthomas.
• Secondary hypercholesterolemia due to hypothyroidism, nephrotic syndrome, or chronic liver disease.
• Diabetes mellitus – especially when poorly controlled, can raise triglyceride‑rich lipoproteins.
• Obesity – contributes to the metabolic milieu that raises LDL and triglycerides.
• Cholesterol‑lowering medication non‑adherence – uncontrolled levels after stopping statins or PCSK9 inhibitors.
• Rare disorders such as sitosterolemia (plant sterol accumulation) or cerebrotendinous xanthomatosis (defective bile‑acid synthesis).

Associated Symptoms

Because tendinous xanthomas are a cutaneous marker of systemic lipid disease, they are often accompanied by other signs:

• Coronary artery disease (CAD) – chest pain, shortness of breath, or a history of myocardial infarction.
• Peripheral arterial disease – claudication, cold feet, or ulcerations.
• Arcus senilis – a white‑gray ring around the cornea (more common in young patients with FH).
• Other cutaneous xanthomas – tuberous xanthomas on elbows/knees, eruptive xanthomas on buttocks, or palmar/planar xanthomas.
• Heberden‑type joint pain – due to tendon inflammation secondary to plaque bulk.
• Family history of early‑onset heart attack or lipid disorders.

When to See a Doctor

Even though the plaques themselves rarely cause acute harm, they warrant prompt medical evaluation because they signal increased cardiovascular risk. Seek care if you notice:

• New yellow‑orange nodules on a tendon, especially if they grow rapidly.
• Any chest discomfort, shortness of breath, or palpitations – possible heart‑related complications.
• Family history of early heart attack (<55 years in men, <65 years in women) or known FH.
• Pain, swelling, or reduced range of motion in the affected tendon.
• Skin changes elsewhere (e.g., eruptive xanthomas) indicating severe hypertriglyceridemia.

Diagnosis

Diagnosing tendinous xanthoma plaques involves a combination of clinical assessment, imaging, and laboratory tests.

Clinical examination

• Visual inspection – yellow‑orange colour, often well‑defined.
• Palpation – rubbery, non‑tender, may be attached to underlying tendon.
• Assessment of distribution – Achilles, extensor tendons of the fingers, patellar tendon are classic sites.

Imaging studies

• Ultrasound – shows hyperechoic, heterogeneous deposits within the tendon; useful for monitoring size.
• MRI – provides detailed soft‑tissue contrast; identifies deep infiltration and distinguishes from tendon rupture or tumor.
• CT scan (rare) – may detect calcified plaques.

Laboratory evaluation

• Lipid panel (fasting): total cholesterol, LDL‑C, HDL‑C, triglycerides.
• Genetic testing for LDLR, APOB, PCSK9 mutations if familial hypercholesterolemia is suspected.
• Thyroid function tests (TSH, free T4) – to rule out secondary hyperlipidemia.
• Liver and kidney function tests – assess for nephrotic syndrome or cholestatic disease.

Biopsy (rare)

In ambiguous cases, a punch or excisional biopsy can confirm the presence of lipid‑laden macrophages. Histology shows foamy cells within the tendon’s extracellular matrix.

Treatment Options

Therapy focuses on two goals: reducing the size or preventing progression of the plaques and, most importantly, lowering cardiovascular risk.

Medical management

• Statins (e.g., atorvastatin, rosuvastatin) – first‑line agents that lower LDL‑C by 30‑50 % and can cause modest regression of xanthomas.
• PCSK9 inhibitors (alirocumab, evolocumab) – powerful LDL‑C reducers, especially useful in homozygous FH or statin‑intolerant patients.
• Ezetimibe – blocks intestinal cholesterol absorption; often combined with statins.
• Bile‑acid sequestrants (cholestyramine) – adjunctive therapy when LDL remains high.
• Fibrates (fenofibrate) – primarily lower triglycerides; indicated if hypertriglyceridemia co‑exists.
• Niacin – can raise HDL‑C and lower LDL‑C but is less used due to side‑effects.
• Fish‑oil omega‑3 supplements – modest triglyceride reduction, beneficial for overall cardiovascular health.

Procedural / surgical options

• Excisional surgery – removal of large, symptomatic plaques; generally considered when the lesion interferes with mobility or causes pain.
• Liposuction‑assisted removal – less invasive, used for extensive plaques on the hand extensors.
• Laser therapy (e.g., CO₂ laser) – experimental; may decrease plaque thickness but data are limited.

Home & lifestyle measures

• Adopt a heart‑healthy diet – low in saturated fats, trans fats, and refined carbohydrates; emphasize fruits, vegetables, whole grains, nuts, and fatty fish.
• Maintain a healthy weight – BMI < 25 kg/m² reduces LDL‑C and triglycerides.
• Exercise regularly – at least 150 minutes of moderate‑intensity aerobic activity per week improves lipid profile.
• Avoid tobacco and limit alcohol – both worsen lipid abnormalities.
• Medication adherence – set reminders, use pill organizers, and discuss side‑effects with a clinician.

Prevention Tips

Because tendinous xanthomas are a manifestation of chronic lipid excess, primary prevention hinges on controlling cholesterol from an early age.

• Screen family members if a relative has confirmed FH; cascade testing can identify asymptomatic carriers.
• Obtain a baseline fasting lipid panel by age 20 (or earlier if family history is strong).
• Follow pediatric lipid‑screening guidelines for children with a parent who has FH.
• Implement dietary counseling early in life – teach children about balanced meals and limit sugary drinks.
• Encourage regular physical activity in schools and at home.
• Start pharmacologic therapy promptly when indicated; delayed treatment increases plaque formation risk.
• Monitor lipid levels every 6–12 months while on therapy, adjusting medications as needed.

Emergency Warning Signs

Key Take‑aways

Tendinous xanthoma plaques are not merely a cosmetic issue; they are a visible clue that systemic lipid metabolism is out of balance, often putting patients at high risk for early cardiovascular disease. Prompt recognition, thorough lipid evaluation, and aggressive lipid‑lowering therapy can both improve the skin lesions and, more critically, reduce the chance of heart attack or stroke.

References:

• Mayo Clinic. “Familial hypercholesterolemia.” Updated 2023. Link
• American Heart Association. “Understanding Cholesterol and Lipids.” 2022. Link
• National Institutes of Health. “Statins: How They Work.” 2021. Link
• Cleveland Clinic. “Xanthomas – Skin Signs of Lipid Disorders.” 2024. Link
• World Health Organization. “Global Recommendations on Physical Activity for Health.” 2020. Link

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