Dr. Greene, my 12-year-old son has a sore lump directly under his nipple. Could this be puberty related? This lump is tiny and hard and underneath the skin of the nipple. Thanks for your help!
Alberta, Canada

Dr. Greene’s Answer:

Lumps of one kind or another are a common reason for a visit to the doctor’s office. The lump might be in the neck (that the parents suspect is just a swollen gland), in the knee (that the parents think is from sliding into third base last month), or under the nipple (that the parents hope is due to puberty). I often enjoy seeing parents with these concerns in my own office. Sometimes the parents feel that they shouldn’t even bother their doctor with this because it’s probably normal. But underneath these hopeful, at-home diagnoses lies a common fear for breast lumps in boys–it might be a tumor!

Most lumps in children are not cancerous and are not serious. Thankfully, childhood cancer is uncommon. But parents’ fears are not unfounded. Childhood breast cancer is quite rare, but it certainly does occur, even in boys. In males of all ages, breast cancer accounts for less than 1% of all cancers (American Surgeon, 1999; 65:250–253). But if it is your son, any chance of cancer seems too much. And a lump might be the first sign noticed.

Breast lumps in children often give rise to two immediate fears–Could it be a tumor? Or could something be going wrong with puberty? (A third fear–Will my child be teased?–arises if the first two turn out to be no problem.)

When to be Concerned about Breast Lumps in Boys & When to Relax

I’ll give you some guidelines for when to be concerned about a breast lump and when you can relax.

Puberty is a time of dramatic changes in the body, especially in the reproductive system. These transformations are brought about by surges of complex and precisely balanced hormones. The last time your 12-year-old had these tides of hormones was when he was a newborn–but then the hormones were yours. Coursing through his blood, your hormones matured his lungs, made him ready for life in the big outside world, and along the way may have given him baby acne and breast enlargement–even nipples that leaked milk. This precious newborn season was gone in a blink.

Now your 12-year-old is making surges of these same hormones on his own as his body turns into an adult’s–a miracle not unlike when you helped turn his body into a newborn’s.

There are five stages of the changes that occur during puberty, called Tanner stages or Sexual Maturity Rating (SMR) stages. Breast lumps in boys are common during SMR 3 and SMR 4.

In boys, SMR 3 usually begins at about age 12 or 13 years and lasts a year or so, although it can be normal in our culture to begin as early as 10 years or as late as 14.9 years, according to Tanner (Journal of Pediatrics, 1985; 107:317). SMR 3 is the time when the testes get clearly larger, the penis gets noticeably longer (then thicker in SMR 4), and the pubic hair (though still small in amount) gets darker and starts to curl.

Sperm is first produced during SMR 3.

Boys grow at their fastest during SMR 3 and SMR 4 (girls get their growth spurts earlier). With your son, you’re probably seeing him outgrow his beginning-of-the-year school clothes already–especially his shoes. During SMR 3, the feet and hands usually grow first, then the arms and legs, and finally the trunk–giving them that adorable adolescent gawky look (don’t tell my 12-year-old son I said that).

SMR 3 also marks the beginning of significant underarm perspiration (the odor, as you’ve probably noticed, can start much earlier).

And teenage acne usually begins at SMR 3, continuing on until the end of puberty.

In newborns, baby acne and breast buds often occur at about the same time. In the same way, many adolescent boys develop gynecomastia–true mammary breast tissue in a male–during SMR 3. The firm lump may occur under only one nipple, under both nipples, or under the two at different rates or sizes. The lumps are often tender when they are growing the fastest. In at least 90% of kids, these will go away on their own. They may disappear as quickly as in a few months, but it is not unusual for them to last up to 2 years (Nelson Textbook of Pediatrics, WB Saunders, 2004). In some children, they may persist without being a problem. Gynecomastia occurs in at least 40% to 60% of boys (Fortschritte der Medizin, 1998; 116:23–26).

Gynecomastia can run in families, and when it does, the disappearance pattern tends to be similar in the family. Gynecomastia can happen in boys of any size but it is more common in bigger teens–either taller, heavier, or both. Obesity can certainly be a cause of gynecomastia in some children (Clinical Pediatrcs, 1998; 37:367–371).

Gynecomastia is different, though, than fatty tissue in the breast area. Boys tend to store extra fat in the upper body (breast and abdomen area), but girls are much more likely to store it in the lower body, particularly the thighs (Pediatrics, 1998; 102:e4). This is the first place it goes on and the last place it comes off. If girls’ breasts do enlarge by storing fat, this is usually one of the first places it disappears with weight loss.

Times to Worry about Breast Lumps in Boys (Not a Newborn)

  • If they begin before age 10 years or after age 15 years (especially after puberty is complete)
  • If they are not directly under the nipple
  • If there is overlying dimpling of the skin, skin ulceration, or change in the color of the skin
  • If the they feel fixed to the skin
  • If they are large–over 1.5 inches (4 cm) in diameter
  • If they don’t go away within 2 years
  • If the nipples leak milk, blood, pus, or other fluid
  • If there are other signs of disease–night sweats, fever, or weight loss, for example

These are all situations in which a breast lump should definitely be examined, in addition to the important regularly scheduled physicals during the puberty years. These children should have a careful physical examination right away. They should probably have an endocrinology (hormone) workup and perhaps an ultrasound or a mammogram, depending on the exam. I would also consult with a health care provider if a breast lump is associated with any signs of infection, such as sudden increased size, warmth, tenderness, drainage, redness, or fevers.


In a recent study at Johns Hopkins University of 60 high-risk boys with large lumps (> 4 cm), most of the boys–45 of them–turned out to be fine, but 15 did have significant medical problems, including one who had a serious cancer. Most of the problems were genetic (such as Klinefelter’s syndrome–XXY boys) or hormonal problems that needed to be treated (Clinical Pediatrics, 1998; 37:367–371). Gynecomastia can also be a side effect of taking steroids or other medications. It can come from liver disease, testicular disease, or neurologic diseases.

If you are ever unsure whether a breast lump is normal, it is always wise to seek the advice and opinion of your child’s doctor.

Good Breast Health Practices for Teens

  • Avoiding steroid supplements
  • Avoiding steroid medicines where possible (e.g., keep asthma well controlled with preventive measures)
  • Avoiding cigarette smoking and exposure to second-hand smoke
  • Avoiding alcohol
  • Being physically active daily (exercise)
  • Eating a healthy, whole food diet
  • Maintaining ideal weight
  • Avoiding piercing and tattooing

If normal, benign gynecomastia is bothersome, either because it is large or because it doesn’t go away as puberty progresses, treatment is possible. Sometimes hormones are given to try to shrink the breast tissue. Alternatively, the mammary breast tissue can be removed. A tiny incision is made under the armpit, and the tissue is removed with a fiberoptic scope. The results are great, and the scar is small and inconspicuous (Annals of Plastic Surgery, 1998; 40:62–64).

Normal, small gynecomastia is yet another reminder of the wonderful changes in your son’s body as he becomes a man. While teenagers can be quite trying to live with at times, savor every moment you can as you enter the last few years of having your son in your home.

Did this article help answer your questions on Breast Lumps in teens? Do you still have questions? Let us know in the comments below.

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Dr. Alan Greene Founder of DrGreene.com

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