How is hyperplasia defined in pathological terms?

Hyperplasia is defined as an increase in the number of cells within a tissue, which often leads to the enlargement of that tissue or organ. This phenomenon can occur in response to various stimuli, such as hormonal changes or increased functional demands on the tissue. It is important to understand that hyperplasia refers specifically to an increase in cell proliferation and does not imply a change in the size of individual cells, nor does it indicate any malignancy or replacement of cell types.

In the context of pathophysiology, hyperplasia can be a physiological process, such as in the case of the endometrial lining thickening during the menstrual cycle, or it can be a pathological process, characterized by excessive growth due to various underlying conditions. Importantly, while hyperplastic tissues can display increased cellularity, the cells typically remain normal in appearance and function, distinguishing hyperplasia from neoplastic processes where malignancy may be present.