Micromastia (also called hypomastia, breast aplasia, breast hypoplasia, or mammary hypoplasia) is a medical term describing the postpubertal
underdevelopment
Underdevelopment, in the context of international development, reflects a broad condition or phenomena defined and critiqued by theorists in fields such as economics, development studies, and postcolonial studies. Used primarily to distinguish sta ...
of a woman's
breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues.
In females, it serves as the mammary gland, which produces and secret ...
tissue. Just as it is impossible to define 'normal' breast size, there is no objective definition of micromastia. Breast development is commonly asymmetric and one or both breasts may be small. This condition may be a congenital defect associated with underlying abnormalities of the pectoral muscle (as in
Poland's syndrome
Poland syndrome is a birth defect characterized by an underdeveloped chest muscle and short webbed fingers on one side of the body. There may also be short ribs, less fat, and breast and nipple abnormalities on the same side of the body. Typical ...
), related to trauma (typically
surgery
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...
or
radiotherapy
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radia ...
) or it may be a more subjective aesthetic description.
Self perceived micromastia involves a discrepancy between a person's body image, and her internalized images of appropriate or desirable breast size and shape. Societal ideals over breast size vary over time, but there exist many conceived ideas involving breasts and sexual attractiveness and identity across different cultures.
Causes
Micromastia can be a
congenital
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
or
acquired disorder
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
and may be unilateral or bilateral.
Congenital causes include
ulnar–mammary syndrome
Ulnar–mammary syndrome or Schinzel syndrome is a cutaneous condition characterized by micromastia, nipple and breast hypoplasia or aplasia. Features of UMS can be mild to severe and can vary significantly from person to person, even within the s ...
(caused by
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
s in the
TBX3
T-box transcription factor TBX3 is a protein that in humans is encoded by the ''TBX3'' gene.
T-box 3 (TBX3) is a member of the T-box gene family of transcription factors which all share a highly conserved DNA binding domain known as the T-box. Th ...
gene),
Poland syndrome
Poland syndrome is a birth defect characterized by an underdeveloped chest muscle and short webbed fingers on one side of the body. There may also be short ribs, less fat, and breast and nipple abnormalities on the same side of the body. Typical ...
,
Turner syndrome
Turner syndrome (TS), also known as 45,X, or 45,X0, is a genetic condition in which a female is partially or completely missing an X chromosome. Signs and symptoms vary among those affected. Often, a short and webbed neck, low-set ears, low hair ...
, and
congenital adrenal hyperplasia
Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders characterized by impaired cortisol synthesis. It results from the deficiency of one of the five enzymes required for the synthesis of cortisol in the adrenal cortex. ...
.
There is also a case report of familial hypoplasia of the nipples and athelia associated with mammary hypoplasia that was described in a father and his daughters.
Acquired causes of micromastia include
irradiation
Irradiation is the process by which an object is exposed to radiation. The exposure can originate from various sources, including natural sources. Most frequently the term refers to ionizing radiation, and to a level of radiation that will serve ...
in infancy and childhood and surgical removal of prepubertal
breast bud.
Treatment
The procedure to remedy micromastia is
breast enlargement Breast enlargement is the enlargement of the breasts. It may occur naturally as in mammoplasia or may occur artificially through active intervention. Many women regard their breasts, which are female secondary sex characteristics, as important to th ...
, most commonly
augmentation mammoplasty
Breast augmentation and augmentation mammoplasty is a cosmetic surgery technique using breast-implants and fat-graft mammoplasty techniques to increase the size, change the shape, and alter the texture of the breasts. Augmentation mammoplasty is ...
using
breast implants
A breast implant is a prosthesis used to change the size, shape, and contour of a person's breast. In reconstructive plastic surgery, breast implants can be placed to restore a natural looking breast following a mastectomy, to correct congenital ...
. Other techniques available involve using muscle flap-based reconstructive surgery techniques (
latissimus dorsi
The latissimus dorsi () is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline. The word latissimus dorsi (plural: ''latissimi dorsorum'') comes from L ...
and
rectus abdominis
The rectus abdominis muscle, ( la, straight abdominal) also known as the "abdominal muscle" or simply the "abs", is a paired straight muscle. It is a paired muscle, separated by a midline band of connective tissue called the linea alba. It exte ...
muscles),
microsurgical reconstruction
Microsurgery is a general term for surgery requiring an operating microscope. The most obvious developments have been procedures developed to allow anastomosis of successively smaller blood vessels and nerves (typically 1 mm in diameter) whi ...
, or fat grafting.
Another potential treatment is hormonal breast enhancement, such as with
estrogen
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...
s.
See also
*
Amastia
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 othe ...
*
Amazia
Amazia refers to a condition where one or both of the mammary glands is absent (the nipple and areola remain present). This may occur either congenitally or iatrogenically (typically the result of surgical removal and/or radiation therapy). Amaz ...
*
Breast atrophy
Breast atrophy is the normal or spontaneous atrophy or shrinkage of the breasts.
Breast atrophy commonly occurs in women during menopause when estrogen levels decrease. It can also be caused by hypoestrogenism and/or hyperandrogenism in women i ...
*
Breast reconstruction
Breast reconstruction is the surgical process of rebuilding the shape and look of a breast, most commonly in women who have had surgery to treat breast cancer. It involves using autologous tissue, prosthetic implants, or a combination of both wit ...
*
Tuberous breasts
Tuberous breasts (or tubular breasts) are a result of a congenital abnormality of the breasts which can occur in both men and women (also see Hypoplasia), one breast or both. During puberty breast development is stymied and the breasts fail to deve ...
References
External links
{{Congenital malformations and deformations of breast
Congenital disorders of breasts