Hyperplasia
Say it: hy-pur-PLAY-zhuh
Hyperplasia is the enlargement of a tissue or organ through a rise in its number of cells, which still look normal under the microscope.
Definition
What is hyperplasia?
Hyperplasia is the growth of a tissue or organ through an increase in the number of its cells, produced by cell division in response to a stimulus such as a hormone or growth factor. The extra cells look normal under the microscope, and unlike a tumor, the growth stays under the body's control and usually stops when the stimulus is withdrawn. It can happen only in tissues whose cells are able to divide, which is why heart muscle enlarges by hypertrophy instead.
Physiological hyperplasia is part of normal life. Hormones make breast glandular tissue multiply at puberty and in pregnancy and the uterine lining thicken in each menstrual cycle, and when part of the liver is removed, the remaining cells divide until much of the lost mass is restored. Pathological hyperplasia usually reflects excess hormonal or growth-factor stimulation. Benign prostatic hyperplasia, a very common enlargement of the prostate in older men linked to age-related hormone changes, can squeeze the urethra and make it hard to empty the bladder. Excess estrogen causes endometrial hyperplasia and abnormal uterine bleeding.
Hyperplasia is not cancer, but repeated cell division gives more opportunities for mutations, so some forms, such as atypical hyperplasia of the endometrium or breast, raise the risk of cancer and are watched or treated.
Word parts
Where does the word “hyperplasia” come from?
- hyper-
- over, excessiveGreek hyper
- -plasia
- formation, moldingGreek plasis, from plassein, to mold
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Terms that go with it
- HypertrophyHypertrophy is the enlargement of a tissue or organ because its individual cells grow larger, rather than because the number of cells increases.
- AtrophyAtrophy is the shrinking of a cell, tissue or organ that had reached normal size, usually as cells lose substance in response to reduced demand or support.
- MetaplasiaMetaplasia is the replacement of one mature cell type by another in a tissue, usually as an adaptation to long-term irritation or injury.
- DysplasiaDysplasia is the presence of abnormal-looking, disordered cells within a tissue, a precancerous change that may regress or progress to cancer.
- HormoneA hormone is a chemical messenger released into the blood by a gland or cell that changes the activity of distant target cells with matching receptors.
- CancerCancer is a group of diseases in which abnormal cells divide without control, invade nearby tissue and can spread to distant parts of the body.
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Checked against
Written for biofideX in plain words, after checking these references:
- NCI Dictionary of Cancer Terms: hyperplasia
- NCBI MeSH: Hyperplasia
- NIDDK: Enlarged Prostate (Benign Prostatic Hyperplasia)
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