Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «M»:
Melanoma, ciliary body
Melanoma, ciliary body: See: Intraocular melanoma....
Melanoma, conjunctival: An uncommon eye cancer that arises in the conjunctiva, the clear membrane that covers the outer surface of the eye and the inner part of the eyelids. Conjunctival melanoma accounts for 2% of all eye malignancies and tends, like melanoma of the skin, to occur in lightskinned ...
Melanoma, eye: See: Intraocular melanoma....
Melanoma, intraocular: See: Intraocular melanoma....
Melanoma, iris: See: Intraocular melanoma....
Melanoma, lentigo maligna
Melanoma, lentigo maligna: One of the four clinical types of malignant melanoma and the slowest growing one. It typically begins as a patch of mottled pigmentation that is dark brown, tan, or black on sun-exposed skin, such as on the face....
Melanoma, malignant: See: Melanoma....
Melanoma, nodular: One of the four clinical types of malignant melanoma, typically presents as a raised, distinct, bluish-black tumor that may be encircled by particularly pale skin, most often in middle-aged or older adults....
Melanoma, ocular: A malignant melanoma arising from a structure within the eye. The most common sites of origin are the choroid, ciliary body, and iris. It tends to occur after age 40. The tumor may metastasize from the eye. The most common site of metastasis is the liver. See also: Conjunctival ...
Melanoma, superficial spreading
Melanoma, superficial spreading: One of the four clinical types of malignant melanoma, the most common
type in whites, typically presents as a raised, irregular, colored area that starts in a mole-like shape but spreads across the skin....
Melanoma, uveal: See: Intraocular melanoma....
Melanosis coli (Pseudomelanosis coli): A benign, reversible
condition usually, but not always, associated with long-term use of anthranoid
laxatives in which pigment deposition in the lamina propria of the large intestine results
in a brown to black discoloration of the mucosa (lining) of the
MELAS syndrome: MELAS is
the acronym for Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes.
MELAS is a rare form of dementia.
It is caused by mutations in the genetic material (DNA) in the mitochondria. While most of
our DNA is in the chromosomes in the cell nucleus, another...
Melasma: Pigmentation of the face, most commonly on the malar area (the upper cheek), bridge of nose, forehead, and upper lip, that occurs in half of women during pregnancy. Birth control pills can also cause melasma. However, hormone therapy after menopause does not cause the condition.
Melatonin: A hormone produced by the pineal
gland, melatonin is intimately involved in regulating the
sleeping and waking cycles, among other processes.
Melatonin supplements are sometimes used by people who have
chronic insomnia. Always see your doctor before taking
melatonin, as it is not rec...