xanthomas

Xanthomas are lipid-rich deposits that develop in the skin, tendons, and other tissues as a result of lipid accumulation within macrophages. They are often a sign of an underlying disorder of lipid metabolism or lipid clearance and can occur in otherwise healthy individuals or in association with systemic disease.

Clinical forms include xanthelasma (lipid-rich plaques on the eyelids, the most common form), eruptive xanthomas (clusters of small yellow papules on the trunk and extremities seen with severe hypertriglyceridemia), planar xanthomas (flat, yellowish plaques often on the hands or other regions), tuberous xanthomas (soft, sometimes nodular lesions on elbows, knees, and buttocks), tuberoeruptive xanthomas (a combination of features), and tendinous xanthomas (lipid deposits in tendons, especially the Achilles tendon, seen in familial hyperlipidemias).

Pathophysiology involves uptake of circulating lipids by macrophages in the dermis or subcutaneous tissue, transforming them into foam cells and forming lipid-rich lesions. Histology typically shows foamy histiocytes with cholesterol clefts. Xanthomas can be associated with primary inherited disorders (for example, familial hypercholesterolemia, familial dysbetalipoproteinemia, or hypertriglyceridemia syndromes) or with secondary conditions such as diabetes, hypothyroidism, cholestatic liver disease, nephrotic syndrome, or certain medications.

Diagnosis relies on clinical examination and lipid profiling to identify underlying dyslipidemia; biopsy may be performed when the diagnosis is uncertain. Management focuses on treating the underlying lipid disorder (statins, fibrates, PCSK9 inhibitors, dietary and lifestyle measures) and addressing associated diseases. Cosmetic concerns from xanthomas may be treated with procedures such as laser therapy or excision, though recurrence can occur if lipid abnormalities persist. Prognosis depends on the associated lipid disorder and its cardiovascular risk profile.