Tendon Xanthoma
Cholesterol Nodules on Tendons, and the Two Conditions They Can Point To
A tendon xanthoma is a firm cholesterol deposit on a tendon. It can point to inherited high cholesterol or, less commonly, a rarer disorder called CTX. This page explains what it signals and why a doctor’s assessment matters.
By Xanthelasma.com
What Is a Tendon Xanthoma?
A tendon xanthoma is a firm, usually painless nodule of cholesterol-rich material that forms within or over a tendon. The classic sites are the Achilles tendon at the back of the heel and the extensor tendons on the backs of the hands, with the knees and other tendons sometimes affected. Because the deposit is bound to the tendon itself, it feels hard and fixed rather than soft and mobile, which helps tell it apart from other lumps.
The important point is that a tendon xanthoma is rarely just a cosmetic matter. It is a recognised outward sign of an underlying disorder of cholesterol metabolism, and it warrants medical assessment to find out which one. This page focuses on the two conditions it most often points to, and on what to do about it. There is a closely related overview at our tendon xanthomas page. If your concern is actually the soft yellow patches on the eyelids, that is a different and usually far less serious condition, xanthelasma, explained on our xanthelasma overview, and the broader family is on our xanthomas page.
The First Condition: Familial Hypercholesterolemia
The most common disorder behind tendon xanthomas is familial hypercholesterolemia (FH), an inherited condition that causes very high LDL (“bad”) cholesterol from early in life. FH is passed down in an autosomal dominant pattern, so a child has roughly a one-in-two chance of inheriting it from an affected parent, and it stems from mutations affecting the LDL-receptor pathway that normally clears cholesterol from the blood.
In FH, tendon xanthomas are one of the hallmark physical signs, and they can lead to the condition being recognised when it might otherwise go unnoticed. This matters a great deal, because untreated FH substantially raises the risk of early cardiovascular disease. Finding a tendon xanthoma can therefore be genuinely valuable: it prompts a cholesterol check and, where FH is confirmed, treatment that markedly lowers that risk. Because it is inherited, a diagnosis also has implications for close relatives, who may benefit from screening. This is firmly a matter for a doctor.
The Second Condition: Cerebrotendinous Xanthomatosis (CTX)
Less commonly, tendon xanthomas can point to a rarer inherited disorder called cerebrotendinous xanthomatosis (CTX). Unlike FH, CTX is autosomal recessive (both parents must carry the faulty gene) and is caused by a mutation in the CYP27A1 gene, which disrupts the breakdown of cholesterol and leads to abnormal storage of cholesterol and a related substance, cholestanol, in tissues including the tendons and the brain.
CTX matters because it can cause problems beyond the tendons, including neurological symptoms over time, so recognising it early is important. A distinguishing feature is that, unlike FH, blood cholesterol may not be dramatically raised in CTX, which is one reason it can be missed, and why proper specialist assessment is needed to tell the two conditions apart. The practical takeaway is the same either way: tendon xanthomas should be investigated by a doctor, who can determine whether FH, CTX, or another lipid disorder is responsible. Our page on xanthomatosis covers CTX and related systemic conditions in more detail.
Where Tendon Xanthomas Appear and How to Recognise Them
Knowing where to look helps with early recognition. Tendon xanthomas favour tendons that are close to the skin or under regular mechanical stress. The Achilles tendon is the most telling site, where they appear as firm thickenings or nodules and can occasionally cause discomfort or affect ankle movement. The extensor tendons on the backs of the hands are another common location, where they can sometimes limit dexterity, and the tendons of the fingers, knees, and elbows may be involved too.
The features to notice are a hard, painless nodule that feels attached to the tendon, gradual thickening of a tendon over time, or subtle stiffness in movement. Some are obvious; others are easy to mistake for a callus or a minor lump. If you have a family history of high cholesterol or early heart disease, any such finding deserves particular attention. The sensible response to a suspected tendon xanthoma is always to have it checked rather than to watch and wait, because what it may be signalling is worth catching early.
If You Were Looking for the Eyelid Type
People often arrive at a page like this after searching broadly for “xanthoma” when what they really have is the eyelid form, the soft yellow patches called xanthelasma. If that is your situation, it is a different and generally far less worrying matter. Eyelid xanthelasma is usually a straightforward cosmetic concern, and around half of those affected have completely normal cholesterol, though a simple cholesterol check is still sensible.
If your concern is the eyelid marks, you can read about them on our xanthelasma overview or see what xanthelasma looks like to confirm. For deposits on tendons, the Achilles, the hands, the fingers, please see a doctor for a cholesterol assessment, as these need proper medical care rather than a cosmetic approach.
The Bottom Line on Tendon Xanthoma
A tendon xanthoma is a firm cholesterol deposit on a tendon, and its significance lies in what it can point to: most often familial hypercholesterolemia, an inherited cause of very high cholesterol with real cardiovascular implications, and less commonly the rarer disorder CTX. Either way, it is a sign to see a doctor for a lipid work-up and assessment, not a cosmetic problem to treat at home.
If your concern turns out to be the common eyelid plaques known as xanthelasma, that is a much simpler, cosmetic matter, and you can start with our xanthelasma overview or the related tendon xanthomas page for more on the tendon form. For tendon deposits, please see your doctor.
Common Questions About Tendon Xanthoma
What is a tendon xanthoma?
It is a firm, usually painless nodule of cholesterol-rich material that forms within or over a tendon, classically the Achilles tendon or the tendons of the hands. It feels hard and attached to the tendon. It is an outward sign of an underlying cholesterol disorder and warrants medical assessment rather than cosmetic treatment.
What does a tendon xanthoma indicate?
Most often it indicates familial hypercholesterolemia, an inherited condition causing very high LDL cholesterol, and less commonly a rarer disorder called cerebrotendinous xanthomatosis (CTX). Both are inherited and both warrant medical care. A tendon xanthoma is therefore an important prompt for a lipid work-up and assessment.
What is the difference between FH and CTX?
Familial hypercholesterolemia (FH) is autosomal dominant, involves the LDL-receptor pathway, and usually causes markedly high blood cholesterol. CTX is rarer, autosomal recessive, caused by a CYP27A1 mutation, and may not show dramatically high cholesterol, but can cause neurological problems over time. Telling them apart needs medical assessment.
Are tendon xanthomas the same as eyelid xanthelasma?
No. Both are cholesterol deposits, but tendon xanthomas form on tendons and point to significant, often inherited, cholesterol disorders needing medical care, while eyelid xanthelasma is usually a simple cosmetic concern, with around half of those affected having normal cholesterol. A cosmetic cream is relevant only to the eyelid form.
Can a tendon xanthoma be removed with a cream?
No. A tendon xanthoma is a medical matter tied to an underlying lipid disorder, not something a cosmetic cream is intended for. It needs medical assessment and management of the underlying cause. Surgery is occasionally considered only if a nodule causes pain or limits tendon movement.
Will a tendon xanthoma go away if I lower my cholesterol?
Managing the underlying disorder is the priority and protects your wider health, and over time good cholesterol control can sometimes reduce the deposits. However, this is a long-term, doctor-led process focused on the underlying condition rather than the appearance of the nodule.
Where do tendon xanthomas usually appear?
Most often on the Achilles tendon at the back of the heel and the extensor tendons on the backs of the hands, and sometimes on the fingers, knees, or elbows. They favour tendons close to the skin or under regular stress. Any firm nodule attached to a tendon in these areas is worth having checked.
What should I do if I find a hard nodule on my tendon?
See a doctor for an assessment. Because a tendon xanthoma can signal an inherited cholesterol disorder with cardiovascular or other implications, getting your blood fats checked and the nodule evaluated is more important than its appearance. Early diagnosis and management of the underlying condition genuinely improve long-term health.
A tendon xanthoma can signal familial hypercholesterolemia or, less commonly, CTX, so it should always be assessed by a doctor, who can arrange the right tests and guide your care. This page is for general information and is not a substitute for medical advice.
