Growth has aptly been described as a physiologic process dependent on some deep, inherent characteristic of living protoplasm at present unknown. A suitable environment, including an appropriate food supply, provides the essentials for growth.1 The medical profession is frequently confronted with perverted growths which are derived from various tissues and organs and which are entirely outside the range of orderly physiologic variation of organ form or bodily development. Thus there are pathologic tumors, either benign or malignant in character, which produce extreme distortions. These furnish special occasions for study and treatment. Growth may be aberrant in quite different ways, leading to distortions or bodily peculiarities that may be described as abnormal rather than pathologic. In this category the anomalies of form and structure belong. Such extremes as gigantism or dwarfism and oddities like polydactylism are familiar.
There are less spectacular manifestations that present equally baffling problems to the student
HEREDITARY ECTODERMAL DYSPLASIA. JAMA. 1929;92(21):1766–1767. doi:10.1001/jama.1929.02700470042017