DIAGNOSIS: Eruptive xanthomas
This patient has eruptive xanthomas secondary to hypertriglyceridemia. His type IV hyperlipidemia has been worsened by long-standing, poorly controlled type 2 diabetes.
Xanthomas are lipid deposits in the skin and tendons that occur secondarily to a lipid abnormality. These lipid deposits are yellow and frequently firm.1 Although certain types of xanthomas are characteristic of particular lipid abnormalities, none is totally specific because the same form of xanthomas occurs in many different diseases.2
Xanthomas occur in various metabolic disorders and can also be associated with neoplasms. They may be associated with familial or acquired disorders resulting in hyperlipidemia or may be present with no underlying disorder.3
Types of xanthomas. Xanthomas are classified into 5 types based on clinical appearance. Tuberous and tendinous xanthomas both occur on the extensors of fingers and Achilles tendon. They appear as yellow nodules. Plane xanthomas are associated with biliary disease and appear as linear yellow lesions. Xanthelasmas appear as yellow plaques on the eyelids. Eruptive xanthomas are yellow papules that appear and disappear according to variations in lipid levels, especially triglycerides.3 As in this case, eruptive xanthomas usually appear over the buttocks, shoulders, back, and extensor surfaces of the extremities.4
Laboratory tests helpful in making the diagnosis
The patient’s tests on hospital admission showed normal cardiac enzymes and a normal electrocardiogram (ECG). His electrolytes were within normal limits except for a pseudohyponatremia of 133 mEq/dL due to an elevated glucose of 549 mg/dL.
A lipid profile the following morning revealed a triglyceride level of 1976 mg/dL, a total cholesterol level of 323 mg/dL, and a high-density lipoprotein (HDL) cholesterol level of 24 mg/dL. The low-density lipoprotein (LDL) cholesterol could not be calculated due to the high triglyceride level.