Any abnormal or pathological growth of tissues or organs resulting in the alteration in size, shape, and organisation of cells. This is contrasted with anaplasia (loss of structural differentiation within a cell or group of cells often with an increased chance of multiplication, as in a malignant tumour), aplasia (failure of some tissue or organ to develop), hyperplasia (abnormal increase in number of cells), hypertrophy (abnormal enlargement of a body part or organ), and hypoplasia (underdevelopment of an organ due to a decrease in the number of cells).
See Aortic hypoplasia, Bronchopulmonary dysplasia, De Morsier-Kallmann syndrome, Hypoplasia