Micromastia

Micromastia, also called hypomastia, breast aplasia, breast hypoplasia, or mammary hypoplasia, is the underdevelopment of breast tissue in a woman after puberty. Because breast size and shape vary naturally and are often asymmetric between the two sides of the body, there is no single objective clinical threshold that defines the condition, and diagnosis instead rests on a discrepancy between a person's actual breast development and the internalized image of an appropriate or expected size and shape. The condition can be congenital, appearing alongside conditions such as Poland syndrome, Turner syndrome, ulnar-mammary syndrome, congenital adrenal hyperplasia, or a familial pattern of mammary hypoplasia, or it can be acquired later through radiation exposure in infancy or childhood or through surgical removal of breast tissue before puberty. It is coded Q83.8 in the ICD-10 for congenital forms. The condition is not communicable, reflecting its developmental or genetic origin rather than any infectious cause.