A 39-year-old man with a prior history of myocardial infarction complains of yellow bumps on his elbows and buttocks. Yellow-colored cutaneous plaques are noted in those areas. The lesions occur in crops and have a surrounding reddish halo.
Which of the following is the best next step in evaluation of this patient?
A. Biopsy of skin lesionsThe description and location of these lesions are suggestive of eruptive xanthomas. Eruptive xanthomas occur primarily on buttocks or extensor surfaces and are associated with elevated triglycerides. Tophaceous gout can result in deposits of monosodium urate, usually in the skin around joints of the hands and feet. Tophi are usually white and may discharge a chalky material. Skin biopsy is not usually necessary to distinguish these lesions. The cutaneous lesions of sarcoidosis (which would usually show disease on CXR) are reddish-brown waxy papules, usually on the face. Obstructive liver disease can occasionally cause palmar xanthomas, which are seen as yellow plaques along the palmar creases.
Xanthomas can be important cutaneous clues for underlying lipid disorders. Xanthelasmas, yellowish plaques on the inner aspect of the upper eyelids, are nonspecific but are associated with hyperlipidemia 50% of the time. Tendon xanthomas are important clues for familial hypercholesterolemia. Tuberous xanthomas, which often present as plaques or even polypoid nodules over pressure points, usually signify hypercholesterolemia. Eruptive xanthomas, again, are associated with triglyceride levels above 1000 mg/dL. Treatment of the hypertriglyceridemia usually results in resolution of lesions. Biopsy of a xanthoma would show lipid-containing macrophages, but is usually not necessary for diagnosis.