Clinical manifestations of dyslipidemia: Types and characteristics of xanthoma

Symptoms of dyslipidemia

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The clinical manifestations of dyslipidemia mainly include two aspects: ① xanthoma caused by lipid deposition in the dermis; ② atherosclerosis caused by lipid deposition under vascular endothelial cells, resulting in cardiovascular and cerebrovascular diseases and peripheral vascular diseases.

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Because the incidence of xanthomas in patients with dyslipidemia is not high, and the occurrence and development of atherosclerosis is relatively insidious, requiring a long time before clinical manifestations appear, most patients with dyslipidemia have no clinical symptoms or signs. Therefore, we call it the "silent killer".

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Patients' abnormal blood lipids are often discovered through biochemical tests during health checkups or when seeking medical attention for cardiovascular or other diseases.

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Xanthoma is an abnormal, localized skin lesion that can be yellow, orange, or brownish-red in color, and can appear as nodules, plaques, or papules. It is generally soft in texture.

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This is mainly due to the aggregation of lipid-phagocytic macrophages (foam cells, also known as xanthomas) in the dermis.

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Based on their location and morphology, xanthomas can generally be classified into the following six types:

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> (1) Tendon xanthoma is a special type of nodular xanthoma that occurs in the tendon area, commonly found in the Achilles tendon, the extensor tendons of the hand or foot, the rectus femoris muscle of the knee, and the deltoid tendon of the shoulder.

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It is a round or oval, hard subcutaneous nodule that adheres to the skin over it, has clear borders, and is not tender.

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This type of xanthoma is often a characteristic pathological manifestation of familial hypercholesterolemia.

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> (2) Palmar crease xanthoma is a linear, flat, yellowish lesion that occurs on the palm. It is orange-yellow in color, slightly raised on the skin surface, and distributed in the creases between the palm and fingers.

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This type of xanthoma has some reference value in diagnosing familial abnormal β-lipoproteinemia.

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> (3) Tuberous xanthoma: This type of xanthoma develops slowly and is common on the extensor side of joints, such as the elbow, knee, finger joints, hip, ankle, and buttock.

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It consists of round nodules of varying sizes with clear borders.

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In the early stages, the texture is relatively soft, but it hardens later due to fibrosis caused by insufficient blood supply.

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This type of xanthoma is mainly seen in diseases such as familial abnormal β-lipoproteinemia or familial hypercholesterolemia.

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> (4) Tuberous eruptive xanthoma: This type of xanthoma commonly occurs on the extensor side of the elbow and buttocks. The lesions often appear in batches within a short period of time, are nodular, and tend to merge. The eruptive xanthoma often surrounds the nodular xanthoma.

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Xanthomas are characterized by an orange-yellow discoloration of the surrounding skin and are often accompanied by an inflammatory base.

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This type of xanthoma is mainly seen in familial abnormal β-lipoproteinemia.

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> (5) Eruptive xanthoma: This type of xanthoma presents as papules the size of a pinhead or match head, which are orange-yellow or brownish-yellow in color and accompanied by an inflammatory base.

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Sometimes the oral mucosa can also be affected.

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It is mainly seen in hypertriglyceridemia.

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> (6) Xanthelasma: This type of xanthelasma is found around the eyelids and is also known as "eyelid xanthelasma". It is a relatively common type of xanthelasma.

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It manifests as flat, yellowish, slightly raised papules or patches on the skin around the eyelids, with clear borders and a soft texture.

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Widespread flat xanthomas can affect the face, neck, trunk, and limbs. They are flat, pale yellow or brownish-yellow papules, ranging in size from a few millimeters to several centimeters, with clear borders and a smooth surface.

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This type of xanthomas is common in various types of hyperlipidemia, but it can also be seen in people with normal blood lipids.

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> (7) Gastric xanthoma is a tumor-like hyperplasia formed by the focal aggregation of macrophages that phagocytose lipids in the gastric mucosa. It is a lesion caused by local lipid metabolism disorders in the gastric mucosa and is also known as gastric xanthoma or lipid island.

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This disease was first reported in 1910, and it appears as yellow or grayish-yellow patches raised on the surface of the gastric mucosa.

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It increases with age, and is more common in patients over 50 years old, with men being more frequently affected.

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The above-mentioned different forms of xanthomas can be seen in different types of dyslipidemia, and the same type of dyslipidemia can present with various forms of xanthomas.

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With effective lipid-lowering treatment, some xanthomas can gradually regress.

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In addition to various xanthomas, two other signs are helpful in diagnosing dyslipidemia: corneal arcus and fundus changes in lipemia.

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Arcus senilis, also known as corneal arcus, is generally seen in the elderly. If it is seen in people under 40 years old, it is often accompanied by hyperlipidemia, most commonly familial hypercholesterolemia. However, this sign is not very specific.

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> Fundus changes in lipemia are caused by the deposition of large lipoprotein particles rich in triglycerides on the small arteries of the fundus, resulting in light scattering. This is often a characteristic manifestation of severe hypertriglyceridemia.

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Severe hypertriglyceridemia can also cause acute pancreatitis, which should be taken seriously.

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In addition, severe hypercholesterolemia, especially homozygous familial hypercholesterolemia, can lead to migratory polyarthritis, although this is relatively rare and the arthritis is usually self-limiting.

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In addition, a small number of patients with dyslipidemia may also experience numbness in the hands and feet, general weakness, dizziness, palpitations, cold sweats, memory loss, insomnia, and lethargy.