iperplasia

Hyperplasia (iperplasia in some languages) is the increase in the number of cells in a tissue or organ, resulting in enlargement due to higher cell counts. It is distinct from hypertrophy, which involves an increase in cell size without a rise in cell number. Hyperplasia can be physiological (normal) or pathological (abnormal).

Physiological hyperplasia occurs as part of normal development or function. Examples include endometrial proliferation under estrogen during the cycle, breast tissue growth at puberty and during pregnancy, and liver regeneration after partial hepatectomy. Pathological hyperplasia arises from persistent stimulation by hormones or growth factors, or as a response to injury. Common examples include endometrial hyperplasia due to unopposed estrogen and benign prostatic hyperplasia related to aging and hormonal changes. Hyperplasia can also occur in other tissues, such as epidermal hyperplasia in response to chronic irritation or infection.

Mechanistically, hyperplasia results from increased cell proliferation driven by growth factors, hormones, or cytokines, and may involve upregulation of cell cycle regulators. It is often reversible if the initiating stimulus is removed and the tissue architecture remains intact. Hyperplasia can be focal or diffuse within an organ.

Clinical significance varies by context. In many cases, hyperplasia is a normal adaptive response. Some hyperplasias, however, carry a higher risk of progression to neoplasia, particularly endometrial hyperplasia with cellular atypia, which can progress toward endometrial carcinoma if untreated. Diagnosis typically relies on histological examination and correlation with clinical factors. Management is directed at removing or mitigating the stimulus, addressing hormonal imbalances, and, when indicated, monitoring or surgical intervention.