Webster's New World Medical Dictionary

malignant 1
Tending to be severe and become
progressively worse, as in malignant hypertension.
2
In regard to a tumor, having the properties of a
malignancy. See also 
malignancy.
malignant giant cell tumor
A type of bone
tumor that is characterized by massive destruction
of bone near the end (epiphysis) of a long bone and
causes pain and restricts movement. The most com-
mon site of malignant giant cell tumor is the knee.
Diagnosis is made by examining a sample of the
affected area. Treatment involves excising the
affected area, usually followed by chemotherapy or
radiation.
malignant melanoma
See 
melanoma.
malleability, brain
See 
brain plasticity.
malleolus
The rounded bony prominence on
either side of the ankle joint.
malleus
A tiny bone in the middle ear that is
shaped like a minute mallet.
malrotated ear
See 
ear, slanted.
malrotation of the intestine
Failure of the
intestine to rotate normally during the development
of the embryo. One of the dangers of malrotation of
the intestine is that the intestine may be obstructed
by abnormal bands or twist on its own blood supply,
a condition called volvulus. Malrotation of the intes-
tine is usually not apparent until the intestine
becomes obstructed or twisted, generally in infants
or in early childhood. Symptoms at that time may
include vomiting up bile (greenish-yellow digestive
fluid), abdominal pain, drawing up the legs, disten-
tion (swelling) of the abdomen, and bloody stools.
This situation is considered an emergency and calls
for immediate surgery to salvage the intestine and
save the child.
MALT lymphoma
A low grade type of malignancy
that arises in cells in mucosal tissue which are
involved in antibody production. These lymphomas
occur most often in the stomach but can also arise
in the lung, thyroid, salivary glands, eye, skin, or
soft tissues. MALT stands for mucosa-associated
lymphoid tissue. MALT lymphomas are typically slow
growing and are usually diagnosed at an early stage.
They may be treated with low doses of radiotherapy
or removed by surgery. If they have spread, they are
treated with chemotherapy. The outlook is good,
even when the disease is quite widespread.
mammary gland
One of the two half-
moon–shaped glands on either side of the adult
female chest, which with fatty tissue and the nipple
make up the breast. Within each mammary gland is
a network of sacs that produce milk during lactation
and send the milk to the nipple via a system of
ducts. Undeveloped mammary glands are present in
female children and in males. See also 
breast;
lactation.
mammogram
An X-ray of the breast that is taken
with a device that compresses and flattens the
breast. A mammogram can help a health profes-
sional decide whether a lump in the breast is a
gland, a harmless cyst, or a tumor. A mammogram
can cause pressure, discomfort, and some soreness
that lasts for a little while after the procedure. If the
mammogram result raises suspicions about cancer,
a biopsy is usually the next step. The American
Cancer Society and the American College of
Surgeons currently recommend that a woman