<unk>  refers to a rare clinical anomaly in which both internal breast tissue and the visible nipple are absent on one or both sides. It affects both men and women.<unk>  can be either isolated (the only medical condition) or comorbid with other syndromes, such as ectodermal dysplasia, syndactaly (Poland's syndrome) and lipoatrophic diabetes. This abnormality can be classified into various types, and each could result from different pathologies.<unk>  differs from amazia and athelia. Amazia is the absence of one or both mammary glands but the nipples remain present, and athelia is the absence of one or both nipples, but the mammary gland remains.<unk>  is presumably due to failure of embryologic (before birth) mammary ridge development or incomplete involution. People with<unk>  often suffer from ectodermal defects, which include various syndromes such as cleft palate, isolated pectoral muscle and abnormal formation of the arms. Treatment for female<unk>  particularly includes psychological guidance and breast reconstruction. Because there is no breast tissue, breastfeeding is not possible. If<unk>  only appears on one side, then it is possible to breastfeed on the other side. Often, people with<unk>  decide against treatment.
Amastia
Hamartia 
Macrodontia 
Macrotia
Acrania
Spotted lunulae
Cystic eyeball
Auricular hypertrichosis