What is hyperplasia?

summary

abnormal increase in cell number

overview

Hyperplasia (ancient Greek hρ huper, "over" + πλάσις plasis, "formation") or hypergenesis is an increase in the amount of organic tissue resulting from cell proliferation . It can lead to gross enlargement of an organ and the term is sometimes confused with benign neoplasia or benign tumor.
Hyperplasia is a common preneoplastic response to stimuli. Microscopically, the cells resemble normal cells, but their number is increasing. Sometimes the cells may also increase in size (hypertrophy). Hyperplasia differs from hypertrophy in that the adaptive cell change in hypertrophy is an increase in the size of the cells, whereas hyperplasia involves an increase in the number of cells.

Among the cells that make up tissues, specific cells undergo various stimuli to cause cell division and the cell number increases, resulting in excessive tissue and organ size. This is also called increase. Unlike tumors that continue to grow unilaterally, there is a limit to growth and if the stimulus is removed it is a reversible reaction that returns tissue size to its original state. Causes of hyperplasia include workload, hormonal influences, and mechanical stimulation. There are also temporary ones during playback. Almost all tissues with hyperplasia are associated with increased function. When it comes to hormonal effects, it is most commonly seen in organs under the influence of the hormone, but is usually caused by a disturbance in the balance between the pituitary gland and endocrine organs. Prostate hypertrophy is due to hyperplasia of the glandular epithelium caused by androgen stimulation and should be termed prostatic hyperplasia. In chronic renal failure, when excretory function is impaired and blood phosphate levels increase, parathyroid hormone hypersecretion occurs due to increased secretion of parathyroid hormone. An example that occurs during regeneration is substantial hematopoiesis of erythroblasts, which occurs in the bone marrow after bleeding. Hyperplasia of the epithelium includes hyperkeratinization of the skin (such as ) due to mechanical stimulation, hyperplasia of the epidermis due to inflammation such as mold, hyperplasia of the crypt epithelium of the gastric ulcer marginal mucosa.
Kazukatsu Yamaguchi

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