Question

A patient presents with xanthomas on the Achilles tendon. Which of the following is the most likely diagnosis?

• A. Familial hypercholesterolemia
• B. Tangier disease
• C. Familial hyperchylomicronemia
• D. Type III hyperlipoproteinemia

Hint:

When diagnosing lipid disorders, look for signs like xanthomas, which are commonly found in familial hypercholesterolemia, especially at sites like the Achilles tendon.

Answer 1

The Correct Option is A

Step 1: Read the key sign.
Xanthomas located on the Achilles TENDON (and other extensor tendons) are tendon xanthomas. The cell type and location of a xanthoma tell you which lipid is in excess, so use the site to back-track to the disorder.

Step 2: Link tendon xanthoma to its lipid.
Tendon xanthomas are cholesterol-laden deposits and are the hallmark of chronically very high LDL cholesterol. Among the options, the disorder defined by grossly elevated LDL is Familial hypercholesterolaemia (an LDL-receptor / ApoB defect, type IIa pattern).

Step 3: Cross out by matching each disease to its own xanthoma/lipid.
$\bullet$ Tangier disease: deficient HDL with orange tonsils and low cholesterol $-$ no tendon xanthomas.
$\bullet$ Familial hyperchylomicronaemia (type I, LPL deficiency): very high triglycerides giving ERUPTIVE xanthomas, not tendon xanthomas.
$\bullet$ Type III hyperlipoproteinaemia (dysbetalipoproteinaemia): raised IDL/remnants giving PALMAR (palmar crease) and tuberoeruptive xanthomas, not Achilles tendon ones.

Step 4: Confirm the match.
Only familial hypercholesterolaemia couples high LDL with the cholesterol-rich tendon xanthomas seen on the Achilles tendon, and it also explains early corneal arcus and premature coronary disease.

Step 5: Conclusion.
Achilles tendon xanthomas point to LDL excess, i.e. Familial hypercholesterolaemia.

Final answer: Option 1 - Familial hypercholesterolemia.