Amastia 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. Amastia can be either isolated (the only medical condition) or comorbid with other syndromes, such as ectodermal dysplasia, syndactaly (Polands syndrome) and lipoatrophic diabetes. This abnormality can be classified into various types, and each could result from different pathologies. Amastia 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.Amastia is presumably due to failure of embryologic (before birth) mammary ridge development or incomplete involution. People with amastia 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 amastia particularly includes psychological guidance and breast reconstruction. Because there is no breast tissue, breastfeeding is not possible. If amastia only appears on one side, then it is possible to breastfeed on the other side. Often, people with amastia decide against treatment. Classification
Amastia can be either iatrogenic or congenital. The congenital amastia are further divided into syndromic type and non-syndromic type respectively. As the definition suggests, syndromic amastia is often associated with obvious symptoms. The common case is hypoplasia of ectodermal tissue, such as hair and skin defects. On the other hand, non-syndromic amastia, shows no defects in body parts other than breast.
Homozygous frameshift mutation in PTPRF may cause amastia, which suggests the causative relationship between PTPRF defect and syndromic amastia. Management
Since bilateral and unilateral amastia may be attributed to different pathologies, appropriate managements should be adopted accordingly. Bilateral amastia can occur in isolation or associated with other disorders. This case is less understood and difficult to treat. On the other hand, Polands syndrome is the most common cause of unilateral amastia. Managements such as muscle/breast reconstruction and nipple areola relocation should be provided to these patients. Breast reconstruction
Surgical treatment for breast defects such as mastectomy is also applicable to treat patients with amastia. Tissue expansion is the most common technique and can be done by using either autologous or prosthetic tissue. For autologous reconstruction, different tissues may be chosen according to patients’ physical condition or their preferences. Prosthetic reconstruction may follow the same principles. Flap reconstruction is another method to rebuild the breast surgically. There are various kinds of flaps to choose depending on different situation. Nipple areola relocation
Amastia is often associated with Polands syndrome, which requires appropriate reconstructive procedure to stabilize chest wall, transfer dynamic muscle and reposition nipple areola region. The treatment of nipple areola relocation provides space for secondary breast enlargement. In this treatment, the tissue expander can be inserted either beforehand or delayed. It can be placed in different parts of body depending on how many overlying soft tissues the patient has.