Amazia refers to a condition where one or both of the mammary glands

Mammary gland

A mammary gland is an organ in mammals that produces milk to feed young offspring. Mammals get their name from the word "mammary". In ruminants such as cows, goats, and deer, the mammary glands are contained in their udders...

 is absent (the nipple

Nipple

In its most general form, a nipple is a structure from which a fluid emanates. More specifically, it is the projection on the breasts or udder of a mammal by which breast milk is delivered to a mother's young. In this sense, it is often called a teat, especially when referring to non-humans, and...

 and areola

Areola

This article is about the breast tissue. For the entomology term, see the glossary of Lepidopteran terms. For an artistic cloud motif, see aureola. For the cactus feature, see Areole....

 remain present). This may occur either congenitally

Congenital disorder

A congenital disorder, or congenital disease, is a condition existing at birth and often before birth, or that develops during the first month of life , regardless of causation...

 or iatrogenically

Iatrogenesis

Iatrogenesis, or an iatrogenic artifact is an inadvertent adverse effect or complication resulting from medical treatment or advice, including that of psychologists, therapists, pharmacists, nurses, physicians and dentists...

 (typically the result of surgical removal and/or radiation therapy). Amazia can be treated with breast implants.

Amazia differs from amastia

Amastia

Amastia refers to a condition where breast tissue, nipple, and areola is absent, either congenitally or iatrogenically. Amastia in girls can be treated with augmentation mammoplasty....

(the complete absence of breast tissue, nipple, and areola), although the two conditions are often (erroneously) thought to be identical. The terms "amazia" and "amastia" are thus often used interchangeably, even though the two conditions are medically different.