A rare breast malformation characterized by congenital absence of breast and nipple (amastia), or nipple or mammary gland (athelia or amazia, respectively). It can be unilateral or bilateral and may occur as an isolated malformation or be associated with a syndrome or cluster of other anomalies.

Scalp-ear-nipple syndrome is characterized by aplasia cutis congenita of the scalp, breast anomalies that range from hypothelia or athelia to amastia, and minor anomalies of the external ears. Less frequent clinical characteristics include nail dystrophy, dental anomalies, cutaneous syndactyly of the digits, and renal malformations. Penetrance appears to be high, although there is substantial variable expressivity within families (Marneros et al., 2013).