Gynaecomastia is the enlargement of male breast tissue. It is common in newborns,
at puberty, as well as in older men.
There is growth of the male breast glands and not just the fat. It may occur in one or
both breasts and it is a benign condition.
Gynaecomastia can be due to the
imbalance of the sex hormones,
testosterone and oestrogen.
Oestrogen is a feminine hormone that
causes the breast tissue to grow. Men
do produce some oestrogen but they
usually have more testosterone which
prevents the effects of oestrogen.
- Hormone imbalance in men can
cause the breasts to grow.
- Obesity increases levels of
oestrogen and is also a common
cause for gynaecomastia.
- In newborn baby boys, oestrogen
can pass through the placenta from
the mother, but this is temporary
and will disappear in a few weeks
- During puberty, hormone levels
change and if the amount of
testosterone drops, teenage boys
can develop gynaecomastia. This
usually clears up after their hormone
levels stabilise and is uncommon
beyond the age of 17 years.
- As men get older, they produce less
testosterone and tend to have more
fat and these can lead to excess
breast tissue growth.
- Medications may sometimes cause
gynaecomastia due to their side
effects on the hormonal pathways.
Common examples include:
- Some heart medications such
as spironolactone, verapamil,
nifedipine, enalapril, digoxin and
- Antibiotics/antifungals like ketoconazole,
isoniazid and metronidazole
- Chemotherapy drugs like methotrexate
- Psychiatric medications like
haloperidol, diazepam and
- Recreational drugs including
alcohol, amphetamines and
- Rarer conditions include tumours
such as pituitary tumours in the
brain, testicular tumours, lung, liver
and kidney cancers, kidney, liver or
thyroid disease or genetic causes
such as Klinefelter syndrome.
- Sometimes the cause is unknown.
This may present as a rubbery or firm
mass that starts from underneath the
nipple and then spreads outwards
over the breast area. There may be
discomfort or tenderness. It may occur
in one or both breasts.
A careful examination of your history
including the use of medications is
important in the diagnosis.
Blood tests to exclude the rarer causes
may be performed, and investigations
may include mammograms and breast
ultrasound if is there is a suspicion of
and to exclude breast cancer.
In general, treatment is not needed for
most cases. If there is an underlying
cause, treating the cause will decrease
the breast enlargement.
For men with gynaecomastia of
unknown cause or have residual
gynaecomastia after treatment of the
cause, medical or surgical treatment
may be considered.
Medical treatment includes drugs such
as Clomiphene and Tamoxifen, which
oppose the action of oestrogens. Up to
50 to 80 percent of patients have been
reported to achieve partial reduction in
breast size with these pharmacologic
Surgery can remove the amount of
breast tissue and the various techniques
include reduction mammoplasty, subcutaneous
mastectomies with or
without liposuction and microdebridement.
In these surgeries, the breast is either
partially or totally removed with
the preservation of the nipple and
There is no increased risk of breast
cancer development in men with
gynaecomastia, but the diagnosis of
cancer needs to be excluded in their
Where to Seek Treatment
Specialist services available at the SingHealth Duke-NUS Breast Centre
National Cancer Centre Singapore
Tel: 6436 8088
Singapore General Hospital
Tel: 6321 4377
Changi General Hospital
Tel: 6850 3333
Sengkang General Hospital
Tel : 6930 6000
KK Women's and Children's Hospital
Tel: 6294 4050