A lump on or near your nipple is usually benign. The most common causes include clogged skin glands, small cysts, hormonal tissue changes, and noncancerous growths in the milk ducts. That said, any new or changing lump deserves a closer look, because the location alone doesn’t tell you what it is.
What’s causing your lump depends on its size, texture, whether it hurts, and whether you have other symptoms like discharge or skin changes. Here’s a breakdown of the most likely explanations.
Clogged Glands on the Areola
The areola (the darker circle around your nipple) is dotted with tiny oil-producing glands called Montgomery glands. Normally they look like small, skin-colored bumps. When one gets clogged, it can swell up and feel firm, similar to a pimple. This is one of the most common reasons people suddenly notice a bump in the nipple area.
In some cases, the duct that drains a Montgomery gland gets blocked deeper inside, forming a fluid-filled pocket behind the areola. This is sometimes called a retroareolar cyst. It shows up as a swollen mass that may or may not hurt. These cysts are benign, but larger ones sometimes need to be drained.
Intraductal Papillomas
An intraductal papilloma is a small, noncancerous growth that forms inside one of the milk ducts near the nipple. If it’s large enough, you can feel it as a tiny lump right behind or beside the nipple. The hallmark symptom is clear or bloody discharge from one nipple, though not everyone gets discharge. These are benign growths, but because bloody discharge can also signal something more serious, imaging and sometimes a biopsy are used to confirm the diagnosis.
Fibroadenomas
Fibroadenomas are solid, noncancerous lumps made of fibrous and glandular tissue. They’re smooth, round, firm or rubbery, and they slide around easily under the skin when you push them. Most range from pea-sized to about 2 to 3 centimeters, though some grow larger. They’re painless. While fibroadenomas more commonly appear elsewhere in the breast, they can develop close to the nipple. They don’t require treatment unless they’re growing or causing discomfort.
Widened Milk Ducts
A condition called mammary duct ectasia happens when a milk duct just beneath the nipple widens and its walls thicken. The duct can fill with fluid and become blocked with a sticky substance, leading to inflammation and a firm area near the nipple. This is most common during perimenopause, roughly between ages 45 and 55.
Along with a lump or thickened spot, you might notice a dirty white, yellowish, green, or black discharge from the nipple, tenderness, color changes in the skin around the nipple, or a nipple that starts to turn inward. It typically resolves on its own, though persistent cases sometimes need treatment.
Infection or Abscess
A subareolar abscess is a pocket of infection that forms just beneath the areola. Pain is often the first thing you notice, followed by a visible or palpable lump with swelling and warmth. The overlying skin may turn red or become discolored, and pus can sometimes leak from the nipple. If you’re experiencing these symptoms, especially with fever, this needs prompt medical attention. Antibiotics taken by mouth for 10 to 14 days are the standard first step, though some abscesses need to be drained.
Fat Necrosis After Injury
If you’ve had any trauma to the breast area, even from something as routine as a seatbelt during a sudden stop, injured fat cells can die and form a lump. This is called fat necrosis. The lump can feel soft and fatty or firm and hard, depending on how far along the healing process is. As the dead fat cells release their oily contents, they can form a pocket called an oil cyst, which may eventually calcify and harden further.
The skin over the area might look red or bruised, and in some cases the nipple can pull inward. Fat necrosis is completely benign, but it can look suspicious on imaging, so your doctor may ask about any prior injuries, surgeries, biopsies, or radiation treatments to put the findings in context. Occasionally a needle biopsy is needed to confirm it isn’t something else.
Lumps in Men
Men can develop nipple lumps too, and the most common cause by far is gynecomastia: a small disc of glandular tissue that grows underneath the nipple due to an imbalance between testosterone and estrogen. It typically feels like a button-sized, rubbery growth centered right behind the nipple.
Gynecomastia can be triggered by certain medications (including some used for heartburn, hair loss, and heart conditions), excess body fat, thyroid problems, or, less commonly, tumors in the adrenal glands, pituitary gland, or testes. Male breast cancer exists but is far rarer than gynecomastia. Still, any hard, fixed, or growing lump in a man’s breast should be evaluated with imaging.
Signs That Need Prompt Evaluation
Most nipple lumps turn out to be harmless, but certain features raise the level of concern:
- A hard lump that doesn’t move or feels different from the surrounding tissue
- Bloody or clear nipple discharge, especially from only one side
- Skin changes such as dimpling, puckering, or thickening over the lump
- Flaking, crusting, or scaling skin on the nipple or areola, which can be a sign of Paget disease of the breast, a rare form of breast cancer
- A nipple that has recently turned inward
- Redness, swelling, or localized pain that doesn’t resolve
- A lump under the arm on the same side
Paget disease deserves special mention because it often looks like eczema or a skin irritation rather than a typical lump. Itching, tingling, redness, and crusty or thickened skin on the nipple that doesn’t heal with standard skin treatments are its hallmark symptoms.
How Nipple Lumps Are Diagnosed
For women, the standard workup for any palpable lump includes a clinical breast exam followed by imaging. Ultrasound and diagnostic mammography are the primary tools, and the choice depends partly on your age and how suspicious the lump looks. For men under 25, ultrasound is typically the first imaging step. For men 25 and older, mammography is generally recommended first.
If imaging doesn’t give a clear answer, a needle biopsy can provide a definitive diagnosis. Many lumps, particularly clogged glands, small cysts, and fibroadenomas, can be confidently identified on imaging alone without needing a biopsy. The key is not to skip the evaluation step. Even lumps that feel “obviously harmless” can occasionally surprise, and a quick ultrasound is a simple way to put the question to rest.