Dictionary

cyclothymia A form of bipolar disorder in which the mood swings are less severe than manic depression. See also bipolar disorder.

cyst A closed sac or capsule, usually filled with fluid or semisolid material.

cyst, Baker See Baker cyst.

cyst, Meibomian An inflammation of the oil gland of the eyelid. Also known as chalazion or tarsal cyst.

cyst, ovarian A fluid-filled sac in the ovary. The most common type of ovarian cyst is a follicular cyst. Other cysts can contain blood; they are called hemorrhagic or endometrioid cysts. Still other types of ovarian cysts are called dermoid cysts, or ovarian teratomas. These bizarre but usually benign tumors can contain many different body…

cyst, pilonidal An abscess that occurs in the cleft between the buttocks. Pilonidal cysts form frequently in adolescence after long trips that involve sitting, and they may be painful. Treatment frequently involves surgery if not responsive to heat applications and antibiotics.

cyst, sebaceous A rounded, swollen area of the skin formed by an abnormal sac of retained oily excretion (sebum) from the sebaceous glands. See also gland, sebaceous.

cyst, synovial, of the popliteal space See Baker cyst.

cyst, tarsal See cyst, Meibomian.

cyst, thyroglossal A fluid-filled sac that is present at birth and located in the midline of the neck. A thyroglossal cyst is a congenital malformation (a birth defect). It results from incomplete closure of a segment of the thyroglossal duct, a tube-like structure that normally closes as the embryo develops. Also called a thyroglossal duct…

cyst, thyrolingual See cyst, thyroglossal.

cyst of the ovary, follicular A fluid-filled sac in the ovary. A follicular cyst is the most common type of ovarian cyst. It results from the overgrowth of a follicle, the fluid-filled cyst that contains an egg, that does not rupture to release the egg. Normally ovarian cysts resolve with no intervention over the course…