St. Luke's Hospital
Located in Chesterfield, MO
Main Number: 314-434-1500
Emergency Dept: 314-205-6990 Patient Billing: 888-924-9200
Find a Physician Payment Options Locations & Directions
Follow us on: facebook twitter Mobile Email Page Email Page Print Page Print Page Increase Font Size Decrease Font Size Font Size
Meet the Doctor
Spirit of Women
Community Health Needs Assessment
Home > Health Information

Multimedia Encyclopedia



    Breast development in a male

    Gynecomastia is the growth of abnormally large breasts in males. It is due to the excess growth of breast tissue, not excess fat tissue.


    The condition may occur in one or both breasts and begins as a small lump beneath the nipple, which may be tender. The breasts often enlarge unevenly. Gynecomastia during puberty is not uncommon and usually goes away over a period of months.

    In newborns, breast development may be associated with milk flow (galactorrhea). This condition usually lasts for a couple of weeks, but in rare cases may last until the child is 2 years old.


    Androgens are hormones that create male characteristics, such as hair growth, muscle size, and a deep voice. Estrogens are hormones that create female characteristics. All men have both androgens and estrogens.

    Changes in the levels of these hormones, or in how the body uses or responds to these hormones can cause enlarged breasts in men.

    More than half of boys develop gynecomastia during puberty.

    Other causes include:

    • Aging
    • Cancer chemotherapy
    • Chronic liver disease
    • Exposure to anabolic steroid hormones
    • Exposure to estrogen hormone
    • Kidney failure and dialysis
    • Lack (deficiency) of testosterone (male hormone)
    • Marijuana use
    • Hormone treatment for prostate cancer
    • Radiation treatment of the testicles
    • Side effects of some medications (ketoconazole, spironolactone, metronidazole, cimetidine (Tagamet))

    Rare causes include:

    • Genetic defects
    • Overactive thyroid
    • Tumors

    Breast cancer in men is rare. Signs that may suggest breast cancer include:

    • One-sided breast growth
    • Firm or hard breast lump that feels like it is attached to the tissue
    • Skin sore over the breast
    • Bloody discharge from the nipple

    Home Care

    Apply cold compresses and use pain relievers ( analgesics) as your health care provider recommends if swollen breasts are also tender.

    Other tips include:

    • Stop taking all recreational drugs, such as marijuana
    • Stop taking all nutritional supplements or any drugs you are taking for bodybuilding

    When to Contact a Medical Professional

    Call your health care provider if:

    • You have recent swelling, pain, or enlargement in one or both breasts
    • There is dark or bloody discharge from the nipples
    • There is a skin sore or ulcer over the breast
    • A breast lump feels hard or firm

    Note: Gynecomastia in children who have not yet reached puberty should always be checked by a health care provider.

    What to Expect at Your Office Visit

    Your health care provider will take a medical history and perform a physical examination.

    Medical history questions may include:

    • Is one or both breasts involved?
    • What is the age and gender of the patient?
    • What medications is the person taking?
    • How long has gynecomastia been present?
    • Is the gynecomastia staying the same, getting better, or getting worse?
    • What other symptoms are present?

    Testing may not be necessary, but the following tests may be done to rule out certain diseases:

    • Blood hormone level tests
    • Breast ultrasound
    • Liver and kidney function studies
    • Mammogram


    If an underlying condition is found, it is treated. Your physician should consider all medications that may be causing the problem. Gynecomastia during puberty usually goes away on its own.

    Breast enlargement that is extreme, uneven, or does not go away may be embarrassing for an adolescent boy. Treatments that may be used in rare situations are:

    • Hormone treatment that blocks the effects of estrogens
    • Breast reduction surgery


    Narula HS, Carlson HE. Gynecomastia. Endocrinol Metab Clin North Am. 2007/36:497-519.

    Ali O, Donohue PA. Gynecomastia. In: Kliegman RM, Stanton BF, Geme JW, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 579.


    • Gynecomastia


      • Gynecomastia


      Tests for Gynecomastia

        Review Date: 7/26/2011

        Reviewed By: Nancy J. Rennert, MD, Chief of Endocrinology & Diabetes, Norwalk Hospital, Associate Clinical Professor of Medicine, Yale University School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

        The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

        A.D.A.M. content is best viewed in IE9 or above, Fire Fox and chrome browser.

        Back  |  Top
        About Us
        Contact Us
        Locations & Directions
        Quality Reports
        Annual Reports
        Honors & Awards
        Community Health Needs

        Brain & Spine
        Sleep Medicine
        Urgent Care
        Women's Services
        All Services
        Patients & Visitors
        Locations & Directions
        Find a Physician
        Tour St. Luke's
        Patient & Visitor Information
        Contact Us
        Payment Options
        Financial Assistance
        Send a Card
        Mammogram Appointments
        Health Tools
        My Personal Health
        Spirit of Women
        Health Information & Tools
        Clinical Trials
        Employer Programs -
        Passport to Wellness

        Classes & Events
        Classes & Events
        Spirit of Women
        Donate & Volunteer
        Giving Opportunities
        Physicians & Employees
        For Physicians
        Remote Access
        Medical Residency Information
        Pharmacy Residency Information
        Physician CPOE Training
        St. Luke's Hospital - 232 South Woods Mill Road - Chesterfield, MO 63017 Main Number: 314-434-1500 Emergency Dept: 314-205-6990 Patient Billing: 888-924-9200
        Copyright © St. Luke's Hospital Website Terms and Conditions  |  Privacy Policy  |  Notice of Privacy Practices PDF  |  Patient Rights PDF Sitemap St. Luke's Mobile