Xanthelasma and xanthoma
Xanthoma is a tumour composed of lipid-filled histiocytes containing lipid material in the cytoplasm. A prominent manifestation of the hyperlipoproteinaemias is xanthomas in soft tissue, tendinous, subperiosteal and intraosseous locations. Tuberous and tendinous xanthomas produce nodular masses in soft tissue and tendons that rarely calcify; tendinous xanthomas are common in the fingers, heel, elbow and knee, at which sites they may erode subjacent bone.
Subperiosteal xanthomas are associated with scalloping of the external cortical surface. Intramedullary deposition of lipids leads to lytic defects and pathologic fractures.
Ultrasonography, CT and MR imaging are favoured for the diagnosis of soft tissue xanthomas. The signal intensity of xanthomas on MR imaging varies. The tumours may be of persistent low to intermediate signal intensity on T1-weighted and T2-weighted spin-echo MR images and may show an inhomogeneous signal pattern. Focal areas of high signal intensity may occasionally be encountered on T2-weighted images, however. Some patients reveal a diffuse speckled pattern of signal intensity within a tendon.
Xanthelasma are xanthoma that appear as yellowish plaques or nodules in the subcutaneous tissues in the periorbital region. They represent an accumulation of lipid-containing macrophages in the dermis. Xanthelasma are dull yellow plaques most often found at the inner angles of the eyelids. They may indicate increased blood cholesterol or triglyceride levels. Measuring your lipid levels may be useful, particularly if there is a history of heart disease in your family. Xanthelasma are seen clinically as oval or elongated yellowish plaques just beneath the skin of the periorbital region. Most commonly, they are noted near the inner canthus of the upper eyelid, although they may be seen on the lower lid as well; they are generally symmetrical in presentation. Inspection and palpation may reveal a soft, semisolid, or calcified texture.
Patients with xanthelasma are typically over 40 years of age, and women are affected nearly twice as often as men.1 The condition may be seen in light-skinned and dark-skinned individuals. Patients with xanthelasma may present because of a cosmetic concern, or the condition may be detected on routine ocular examination. The lesions are neither inflammatory nor painful, and there is no tendency toward malignancy, although the lesions may enlarge and/or coalesce over time. In very rare instances, abnormally large xanthelasmas can interfere with lid function, causing ptosis or lagophthalmos.
In most cases, xanthelasma is diagnosed by the clinical appearance alone, though atypical presentations may prompt the clinician to obtain a biopsy. Laboratory testing of serum lipids is also recommended. While xanthelasma is essentially benign, many patients consider the condition to be cosmetically unacceptable, and opt for removal. Treatment modalities are quite numerous, and include such diverse options as: (1) use of chemocautery agents, such as trichloracetic acid; (2) electrodessication; (3) cryotherapy; (4) CO2 or argon laser ablation; or (5) surgical excision. Scar formation and pigmentary changes are the most common complications of laser or chemotherapy. Chemical cautery and surgical excision tend to produce better results with less risk of subsequent scarring.