A lump behind or beneath the nipple in men is most commonly gynecomastia, a buildup of glandular breast tissue driven by a hormonal imbalance between testosterone and estrogen. It’s rarely cancer. The lifetime risk of a man developing breast cancer is about 1 in 755. Still, any new lump deserves attention because what it feels like, where exactly it sits, and what other symptoms come with it all help determine what’s going on.
Gynecomastia: The Most Common Cause
Gynecomastia is the growth of actual breast gland tissue underneath the nipple. It typically feels firm, dense, or rubbery, and it’s usually centered directly behind the nipple rather than off to one side. You might notice tenderness, swelling, or nipples that feel sensitive when they rub against clothing. It can show up in one breast or both, and the two sides don’t have to match in size.
This happens when your body’s balance of testosterone and estrogen shifts. Every male body produces small amounts of estrogen alongside testosterone, and when that ratio tips, breast tissue can respond. Three life stages are especially common for this: the newborn period, puberty, and older age. In teenagers, the lump often appears during puberty and resolves on its own within six months to two years. In men over 50, declining testosterone makes the condition more likely.
Beyond natural hormone shifts, several medications are strongly linked to gynecomastia. An analysis of the FDA’s adverse event database found that certain antipsychotic medications (particularly risperidone and paliperidone), hair loss drugs like finasteride and dutasteride, and the blood pressure and heart failure drug spironolactone had the highest rates of reported cases. Other antipsychotics including olanzapine, quetiapine, and aripiprazole also appeared. If you started a new medication in the weeks or months before the lump showed up, that connection is worth exploring with your prescriber.
Other contributors include heavy alcohol use, marijuana, anabolic steroids, kidney disease, liver disease, and thyroid disorders. Any condition that lowers testosterone or raises estrogen can be a trigger.
Fat Deposits vs. Glandular Tissue
Not every area of fullness behind the nipple is true gynecomastia. Pseudogynecomastia is the medical term for excess fatty tissue in the chest, and it’s common in men who carry extra weight. The difference is fairly distinct on examination: fat feels soft and tends to spread evenly across both sides of the chest, while glandular tissue feels firmer and more concentrated directly under the nipple. Pseudogynecomastia is also painless, whereas true gynecomastia often comes with at least some tenderness.
This distinction matters because the underlying cause and management differ. Pseudogynecomastia generally improves with weight loss. Gynecomastia, because it involves actual gland tissue, does not shrink with diet and exercise alone.
Infections and Cysts Near the Nipple
A lump that appeared quickly, feels warm to the touch, and hurts may be a subareolar abscess, which is a pocket of infection in the small glands beneath the areola. Signs include a swollen, tender lump with redness and warmth on the overlying skin, sometimes with drainage or pus. You might also feel generally unwell or run a low fever. This type of lump needs medical treatment (typically drainage and antibiotics) and won’t resolve on its own.
Sebaceous cysts, which form when a skin oil gland gets blocked, can also pop up near the nipple. These tend to be round, moveable under the skin, and painless unless they become infected.
When a Lump Could Be More Serious
Male breast cancer is uncommon, but it does exist. Certain characteristics raise the level of concern. Pay attention if the lump is hard, painless, and fixed in place rather than moveable. Skin changes over the lump, dimpling, or retraction of the nipple inward are also red flags.
Nipple discharge in a male is always worth investigating. Discharge that is bloody, comes from only one breast, or leaks on its own without squeezing is especially concerning. If you notice any combination of a lump plus discharge, breast pain, redness, or visible changes to the nipple’s shape, get it evaluated promptly.
How Doctors Evaluate a Male Breast Lump
The process usually starts with a physical exam. Your doctor will feel the lump to assess its size, texture, and location, and check for lymph node swelling under the arms. Because the male breast has limited volume, imaging works a bit differently than it does for women. Ultrasound is highly effective for exploring isolated lumps in men and has become the natural complement to the physical exam. It can distinguish between solid masses, fluid-filled cysts, and normal glandular tissue without any radiation.
Mammography is sometimes used as well, though the smaller amount of breast tissue in men can make it less straightforward to interpret. In most cases, a combination of your history, physical findings, and ultrasound provides a clear answer. A biopsy, done under ultrasound guidance, is reserved for cases where the imaging leaves any doubt or when a solid mass needs further characterization.
What to Expect If It’s Gynecomastia
If the lump turns out to be straightforward gynecomastia, the next step depends on the cause. When a medication is responsible, switching to an alternative often allows the tissue to gradually shrink. When an underlying condition like a thyroid disorder or low testosterone is identified, treating that condition can help. In teenagers going through puberty, doctors typically recommend watchful waiting since most cases resolve naturally.
For gynecomastia that persists beyond two years, the glandular tissue tends to become more fibrous and less likely to regress on its own. At that point, if the size or tenderness is bothersome, surgical removal of the breast tissue is an option. The procedure is generally straightforward, with recovery taking a few weeks.
The most important first step is simply getting the lump checked. The vast majority of male nipple lumps have a benign explanation, but knowing which one you’re dealing with determines whether you need treatment, a medication change, or just reassurance.