Webster's New World Medical Dictionary

cystectomy
Surgery to remove the bladder.
cystic acne
A localized infection (abscess) that is
formed when oil ducts become clogged and
infected. Cystic acne is most common in the teenage
years. Treatment includes avoiding irritants on the
face, including many cleansers and cosmetics, and
in some severe cases, use of steroid or antibiotic
medication. Cystic acne can cause permanent scar-
ring in severe cases and in those who are prone to
forming keloids. See also 
acne vulgaris.
cystic fibrosis
A common grave genetic disease
that affects the exocrine glands and is characterized
by the production of abnormal secretions, leading
to mucus buildup that impairs the pancreas and,
secondarily, the intestine. Mucus buildup in lungs
can impair respiration. Abbreviated CF. Without
treatment, CF results in death for 95 percent of
affected children before age 5; however, a few long-
lived CF patients have survived past age 60. Early
diagnosis is of great importance. Treatment
includes physical therapy to loosen the mucus in the
lungs and use of pancreatic enzymes and medica-
tions to fight dangerous infections of the lungs. One
in 400 couples is at risk for having children with CF.
CF is a recessive trait, so the chance of an at-risk
couple having a child with CF is 25 percent with
each pregnancy. CF is caused by mutations in the
CFTR (cystic fibrosis conductance regulator) gene,
which is located on chromosome 7.
cysticercosis
An infection caused by the pork
tapeworm, Taenia solium. Infection occurs when
the tapeworm larvae enter the body and form cysts
called cysticerci. When cysticerci are found in the
brain, the condition is called neurocysticercosis.
Cysticercosis is contracted by accidentally swallow-
ing pork tapeworm eggs. Tapeworm eggs are passed
in the bowel movement of a person who is infected.
When the tapeworm eggs are inside the stomach,
they hatch, penetrate the intestine, travel through
the bloodstream, and may develop into cysticerci in
the muscles, brain, or eyes. Infection is found most
often in rural, developing countries where hygiene
is poor and pigs are allowed to roam freely and eat
human feces. Cysticercosis is not spread from per-
son to person. However, a person who is infected
with the intestinal tapeworm stage of the infection
(T. solium) sheds tapeworm eggs in bowel move-
ments. Tapeworm eggs that are accidentally swal-
lowed by another person can cause infection.
cystine
An amino acid that is particularly notable
because it is the least soluble of all naturally occur-
ring amino acids and because it precipitates out of
solution in the heritable disease cystinuria. Cystine
tends to precipitate out of urine and form stones
(calculi) in the urinary tract, which can obstruct the
flow of urine. See also 
cystinuria.