Symptoms A-Z

Asymmetrical Breasts Symptoms, Causes & Statistics

Understand asymmetrical breasts symptoms, including 7 causes & common questions.

This symptom can also be referred to as: one breast is larger than the other

Asymmetrical Breasts Symptom Checker

Take a quiz to find out what might be causing your asymmetrical breasts

Asymmetrical Breasts Symptoms

Having asymmetrical breasts is a very common occurrence, especially during breast development in adolescence. This typically resolves by the time the breasts are fully developed. However, 25 percent of women have some breast asymmetry their whole lives which is perfectly normal and not necessarily indicative of an underlying condition. In women who do have more significant differences, these can be related to structural variances or lumps. Most breast lumps in women under 50 are benign but can also be malignant, and any lumps in women over 30 should be evaluated [1,2]. Breast exams, breast imaging, and breast biopsy are all common ways medical providers evaluate breast masses in women.

Common accompanying symptoms of asymmetrical breasts

Symptoms that can be associated with asymmetrical breasts include:

Asymmetrical Breasts Causes

Causes of asymmetrical breasts are described below from most to least common, including those related to development and masses, among others [3,4].

Developmental causes

Causes of asymmetrical breasts related to development may include the following.

  • Puberty: Asymmetry is very common during the development of breasts in adolescence. Commonly, breast asymmetry resolves by the time breasts are fully developed, which typically happens by age 18. The final degree of breast asymmetry cannot be determined until this time.
  • Normal variant: While many women with asymmetrical breasts during puberty will experience resolution of the discrepancy, about 25 percent of adult women have remaining breast asymmetry to varying degrees. This can be normal and does not necessarily reflect any underlying condition or problem.
  • Prepubescent injury: Injury to breast tissue before it has fully developed can lead to breast asymmetry. Trauma, infection, or radiation to one side of the chest are possible injuries that might lead to asymmetric breast growth.

Mass-related causes

Asymmetrical breasts may also be due to a mass in the breast, that can be characterized as one of the following [5].

  • Infection: A breast abscess typically presents as a palpable, swollen mass in one breast with pain, redness, and warmth. Typically, a breast abscess is caused by a bacterial infection. The milk ducts in the breast can also become infected, which is common among women who are breastfeeding.
  • Benign breast mass: Breast asymmetry may be due to a palpable breast mass (a mass in the breast that you can feel). Palpable breast masses are very common, and 90 percent are benign in women between the ages of 20 and 50 [6]. In women under 30, breast masses are commonly bilateral and resolve on their own. Some possible types of benign breast masses include fibrous changes with the menstrual cycle, cysts, or tissue damage following trauma to the breast.
  • Malignant breast mass: There are multiple different types of invasive and noninvasive breast cancer that may be the cause of a breast mass. Typically, malignant breast masses are hard, present in one breast (unilateral), and occur in older women. Malignant masses may also present with pain, overlying skin changes, or nipple discharge.

Other causes

Other causes that may result in breast asymmetry include the following.

  • Skeletal abnormality: Breasts may appear asymmetric due to abnormalities of the bones in the spine or ribs. Rib abnormalities such as fracture or deformity may change the shape of the chest wall leading to asymmetry.
  • Curved spine: Scoliosis is a condition where the spine curves more than usual, both from front to back and from right to left. Severe scoliosis can rotate the torso and give the breasts the appearance of asymmetry even if they are the same size. Scoliosis commonly develops in adolescence.
  • Surgical changes: Lumpectomy (removal of part of the breast tissue) or mastectomy (removal of the entire breast) are common treatments for breast cancer. Some women choose to have reconstructive surgery to maintain breast symmetry, while others do not. Surgical removal of breast tissue is one cause of asymmetrical breasts.

7 Possible Asymmetrical Breasts Conditions

The list below shows results from the use of our quiz by Buoy users who experienced asymmetrical breasts. This list does not constitute medical advice and may not accurately represent what you have.

Breast infection (mastitis)

Mastitis is an infection of the breast tissue that results in breast pain, swelling, warmth and redness of the breast. Mastitis most commonly affects women who are breast-feeding (lactation mastitis), although sometimes this condition can occur in women who aren't breast-feeding.

Rarity: Uncommon

Top Symptoms: fatigue, nausea, breast pain, signs of breast inflammation like redness, swelling or fever, fever

Symptoms that always occur with breast infection (mastitis): breast pain, signs of breast inflammation like redness, swelling or fever

Urgency: Primary care doctor

Breast cyst

A breast cyst is a fluid-filled sac (like a tiny balloon) inside the breast. Breast cysts are common in women. They might cause a little pain, but they are usually benign (not cancerous).

Rarity: Common

Top Symptoms: breast pain, breast lump, painful breast lump, movable breast lump

Symptoms that always occur with breast cyst: breast lump

Symptoms that never occur with breast cyst: armpit lump, fever

Urgency: Primary care doctor

Breast abscess

A breast abscess is a collection of infected fluid, or pus, within the breast that is generally painful, and may cause fever, chills, fatigue, and body aches.

A breast abscess is a complication of mastitis, an infection of the breast tissue, that develops most commonly in breastfeeding women. ...

Asymmetrical Breasts Symptom Checker

Take a quiz to find out what might be causing your asymmetrical breasts


Scoliosis causes a sideways curve of your backbone, or spine. Scoliosis is most common in late childhood and the early teens, when children grow fast.

Rarity: Common

Top Symptoms: spontaneous back pain, shortness of breath on exertion, asymmetrical shoulders, asymmetrical breasts, back deformity

Urgency: Wait and watch

Breast cancer

There are several types of breast cancer, depending on the part of the breast where it starts. The most common types are ductal carcinoma in situ (DCIS), invasive ductal carcinoma and invasive lobular carcinoma.

Women over age 50 with a family history of the disease, and/or certain genetic factors, are most at risk, but anyone can get breast cancer at any age. It is rare in men but does occur.

Symptoms include a lump, thickening, or pain anywhere in the breast or armpit; red, flaky, or irritated breast or nipple skin; nipple discharge; and any area of irregular skin or misshapenness.

Many harmless conditions can cause similar signs, so it is important to see a medical provider about any of these symptoms.

Diagnosis is made through physical examination; imaging such as ultrasound, mammogram, or MRI; and sometimes biopsy.

Treatment involves a combination of surgery, radiation therapy, and chemotherapy.

The best prevention is a combination of screening mammograms as recommended by the medical provider, and monthly self-examination.

Rarity: Uncommon

Top Symptoms: breast pain, armpit lump, breast mass or retraction, breast lump, nipple discharge

Urgency: Primary care doctor

Fibrocystic breast changes

Fibrocystic change is a generalized term used to describe a variety of benign changes in the breast. Symptoms of this condition are breast swelling or pain, as well as nodules, lumpiness, or nipple discharge.

Rarity: Common

Top Symptoms: breast lump, hard breast lump, nipple discharge, rope-like breast lump

Symptoms that always occur with fibrocystic breast changes: breast lump

Urgency: Primary care doctor

Intraductal papilloma

Breast problems such as lumps are very common and often not caused by breast cancer. An intraductal papilloma is such a benign breast lump situated in the milk ducts.

Rarity: Uncommon

Top Symptoms: breast lump, painful breast lump, painless breast lump, white or clear fluid leaking from the breast, nipple lump

Symptoms that never occur with intraductal papilloma: armpit lump

Urgency: Primary care doctor

Asymmetrical Breasts Treatments and Relief

If your breast asymmetry is normal or the result of surgery, this can be resolved at home with bras, padding, or inserts. Most masses in women under 30 are benign and resolve on their own; however, if you are over 30 and you notice a new mass, you should seek treatment sooner than later, especially if you believe you have an infection.

At-home treatments

Treatments for asymmetrical breasts that can be completed at home include:

  • Bras, padding, or inserts: Bras with padding on one side can improve the appearance of asymmetrical breasts. This is especially helpful for adolescents who are self-conscious about breast asymmetry while their breasts are still developing. This is also helpful for people with post-surgical asymmetry due to lumpectomy or mastectomy.
  • Observation If you are under the age of 30 and notice a new breast mass, it is most likely benign. A physician may suggest you monitor the lump at home over the course of several menstrual cycles to see if it changes or resolves on its own.

Medical treatments

You should consult your physician in order to complete the following.

  • Breast exam: If you notice a new breast mass, a physician will likely perform a breast exam. They will examine the breast to look for abnormalities, and palpate both breasts and the area underneath your armpits to feel for abnormalities.
  • Imaging: If you have a new breast mass and are over the age of 30, a physician will likely recommend breast imaging to evaluate the cause of the mass. Mammography, breast MRI, and breast ultrasound are all common forms of breast imaging.
  • Medication: If a physician suspects your breast asymmetry is due to an infection of the breast tissue or milk ducts, they may prescribe antibiotics to treat the infection.
  • Biopsy: If a physician suspects the mass in your breast could be malignant, they may take a biopsy of the breast tissue. A biopsy is when a small piece of tissue is removed from the body to determine the cause of disease.
  • Bracing: If a physician suspects your breast asymmetry is due to abnormal curvature of the spine, they may suggest corrective braces to improve spinal alignment.

When asymmetrical breasts are an emergency

If any of the following apply, you should seek immediate treatment:

  • You are over the age of 30 and notice a new breast lump
  • You suspect you may have an infection in your breast

If you've answered yes to one or more of these questions

Take a quiz to find out what might be causing your asymmetrical breasts

Asymmetrical Breasts Symptom Checker Statistics

People who have experienced asymmetrical breasts have also experienced:

  • 12% Breast Pain
  • 2% Breast Lump
  • 2% Nipple Pain

People who have experienced asymmetrical breasts were most often matched with:

  • 36% Breast Infection (Mastitis)
  • 36% Breast Abscess
  • 27% Breast Cyst

Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

Asymmetrical Breasts Symptom Checker

Take a quiz to find out what might be causing your asymmetrical breasts


  1. Kayar R, Cilengiroglu OV. Breast Volume Asymmetry Value, Ratio, and Cancer Risk. Breast Cancer: Basic and Clinical Research. 2015;9:87-92. NCBI Link
  2. Scutt D, Lancaster GA, Manning JT. Breast Asymmetry and Predisposition to Breast Cancer. Breast Cancer Research. 2006;8(2):R14. NCBI Link
  3. Eidlitz-Markus T, Mukamel M, Haimi-Cohen Y, Amir J, Zeharia A. Breast Asymmetry During Adolescence: Physiologic and Non-Physiologic Causes. The Israel Medical Association Journal. 2010;12(4):203-206. NCBI Link
  4. Breast and Chest Wall Disorders. Children's Hospital of Philadelphia. CHOP Link
  5. Venkatesan A, Chu P, Kerlikowske K, Sickles EA, Smith-Bindman R. Positive Predictive Values of Specific Mammographic Findings According to Reader and Patient Variables. Radiology. 2009;250(3):648-657. NCBI Link
  6. Klein S. Evaluation of Palpable Breast Masses. American Family Physician. 2005;71(9):1731-1738. AAFP Link
  7. Apgar B. Is Asymmetric Breast Tissue a Sign of Malignancy? American Family Physician. 1999;60(5):1527-1528. AAFP Link
  8. Santen RJ. Benign Breast Disease in Women. NCBI. Updated May 25, 2018. NCBI Link

Disclaimer: The article does not replace an evaluation by a physician. Information on this page is provided as an information resource only, and is not to be used or relied on for any diagnostic or treatment purposes.