Amastia: Causes, Pathology, Symptoms, Types, Diagnosis and Treatment

It is a rare congenital condition characterized by the absence of breasts and is sometimes accompanied by other malformations.

The condition is believed to be described in the Bible “We have a little sister, and she has no breasts” (Song of Solomon VIII: 8).

Causes of amastia

Causes associated with the formation of the fetus

Amastia can be associated with acral-renal ectodermal dysplasia and lipoatrophic diabetes and cubaromatic syndrome.
Exposure to carbimazole and dehydroepiandrosterone during the first trimester of pregnancy has been reported to cause amastia.
Bilateral amastia is even rarer, of little known etiology with both autosomal dominant and recessive inheritance.
Intrauterine alteration of the vascular supply (internal thoracic artery or its branches) is believed to play a role.

Acquired causes

• Injuries associated with thoracotomy.
• Radiation therapy burns.
The amastia is distinguished from the amazia in that the breast tissue is absent, but the nipple is present. The Amazon is usually a consequence of radiation or surgery.

Pathology of amastia

During embryonic development, the breasts first appear as ectoderm ridges during the 6th week of gestation.
This ridge thickens and leads to mesodermal compression.
With the additional proliferation of ectodermal cells there is a growth of the same in the mesodermal layer that leads to the formation of clusters that also form lobes.
In the fifth month of gestation, some strands of ectodermal cells sprout from each of these lobes and the central parts undergo apoptosis leading to duct formation.
Similarly, on the surface, apoptosis occurs leading to the formation of pinholes that protrude through the nipples after connecting with the formed ducts.
An inhibition at any stage of this development leads to hypoplasia or aplasia of the breast.

Signs and symptoms of amastia

It is characterized by the absence of breast tissue, nipple, and areola.

Types of amastia

Amastia unilateral

Defined as an amastia involving only one side. It is often seen to be associated with the absence of the pectoral muscle and is called Poland syndrome.

Amastia bilateral

In these cases there is amastia on both sides. It is often associated in 40% of cases with multiple congenital anomalies such as birth defects, which also affect other parts of the body.
The unilateral type of amastia is more common than the bilateral one.

Poland syndrome

Some cases of amastia have an associated absence of the pectoral muscles and associated syndactyly (a condition known as Poland syndrome after its description in 1841).
In 1841, Alfred Poland, an English medical student, published a partial description of the deformity. However, the syndrome was initially described in French and German literature in 1826 and 1839.
Poland syndrome affects 1 in 30,000 live births and is sporadic. It is a constellation of anomalies that present themselves in various ways.
The familial nature of this condition was first observed in 1894 and, more recently, it has been established that it is transmitted as an autosomal dominant trait, which is why it is as common in boys as in girls.
The mild and partial forms of Poland syndrome are more common than the full picture, and are often not diagnosed when they consist only of breast asymmetry and a horizontal anterior axillary crease due to the partial absence of the pectoral muscle. The right side is most commonly affected
Poland syndrome is the best known of a series of rare inherited disorders of breast development.

Diagnosis of amastia

Diagnosis is based on the appearance of certain clinical features, inspection, and palpation.


The treatment option consists of reconstructive cosmetic surgery, and the end of pubertal development must be awaited.
Surgical repair is rarely required, except in patients with aplasia of the ribs or a major depressive deformity (Poland syndrome).
When necessary, reconstruction of the chest wall with correction of the contralateral protrusions of the carinatum type can be performed at the same time.
Autologous rib grafts, or a variety of biopro agents
Therapeutic, they can be used with or without a latissimus dorsi flap.
The use of custom chest wall prostheses has been associated with significant problems, such as migration, erosion of local tissues, and adverse cosmesis.
Chest wall reconstruction should be done before breast reconstruction.