Dictionary

xanthoma, eruptive Xanthoma that is linked to lipid disorders and is accompanied by a pink-to-red raised rash.

xanthoma, diabetic Xanthoma that is associated with poorly controlled diabetes mellitus. Treating the diabetes causes diabetic xanthomas to disappear.

xanthoma A firm yellow, orange, or brown nodule deep in the skin (such as around the Achilles tendon, elbows, or knees) or mucous membrane caused by fat deposition. Although xanthomas themselves are harmless, they frequently indicate underlying disease, such as diabetes, lipid disorders (such as elevated blood cholesterol levels), or other conditions. They are composed…

xanthinuria A rare metabolic disorder that is caused by lack of an enzyme needed to process xanthine, an alkaloid found in caffeine; theobromine; theophylline; and related substances. Unchecked, xanthinuria can lead to kidney stone formation. Treatment involves avoiding foods and drinks that contain xanthine derivatives, such as coffee, tea, and cola. Classic xanthinuria is inherited…

xanthelasma Tiny, slightly raised, yellowish plaques on the skin surface of the upper or lower eyelids. Xanthelasma is a harmless growth of tissue caused by tiny deposits of fat in the skin, and it is often associated with abnormal blood fat levels (hyperlipidemia). Xanthelasma is composed of lipid-laden foam cells called histiocytes. Treatment is directed…

X chromosome The sex chromosome that is found twice in normal females and singly, along with a Y chromosome, in normal males. The complete chromosome complement consists of 46 chromosomes, including the 2 sex chromosomes, and is thus conventionally written as 46,XX for chromosomally normal females and 46,XY for chromosomally normal males.

X In genetics and medicine, X chromosome.

Wt Abbreviation for weight. For example, “Wt 80 lbs” means “weight 80 pounds.”

WS Waardenburg syndrome.

wryneck See torticollis, congenital.

writer’s cramp See cramp, writer’s.

wrist The part of the hand that is nearest the forearm and consists of the carpal bones and the associated soft tissues. The eight carpal bones are arranged in two rows. One row of carpal bones joins the long bones of the forearm (the radius, and, indirectly, the ulna). Another row of carpal bones meets…