Medically reviewed guide · Last updated: 11 November 2026 · Reading time: approx. 10 min

Breast Lump: Cyst, Fibroadenoma or Cancer — What Needs Checking

The most common causes compared

The causes in detail

This article is about the palpable lump: what could it be, how is it assessed, and when is it urgent? If your breast feels tight or sore without a lump, our article on breast tenderness will help. If breast cancer has already been diagnosed, you will find treatment and outlook under breast cancer. First things first: most lumps are benign. Whether a particular lump is benign, however, cannot be reliably determined by touch — so every new lump should be seen at the practice once, without panic, but also without months of waiting.

Cysts

Cysts are fluid-filled cavities in the glandular tissue. They feel firm-elastic, round and mobile, can develop within a few days and may become larger and tender to pressure before a period. They are most common between about 35 and the menopause, and afterwards mainly in women on hormone replacement therapy. They can usually be identified clearly on ultrasound. Simple cysts are harmless and do not need treatment; a large, painful cyst can be drained with a fine needle. Cysts with solid components are investigated further.

Fibroadenomas

Fibroadenomas are benign lumps made of glandular and connective tissue, typical in younger women. They feel firm, smooth and rubbery and slip away under the fingers — which is why they are sometimes called a “breast mouse”. They are usually painless and hardly grow. If the ultrasound findings are clear, a follow-up check is often enough; if there is uncertainty, growth or above a certain age, a core needle biopsy confirms the diagnosis. Rarely, a similar-looking lump grows rapidly — a so-called phyllodes tumour, which is removed surgically.

Fibrocystic changes and lumpy glandular tissue

Many women feel granular, lumpy tissue before their period, often on both sides and in the upper outer area. This is a benign, hormone-dependent remodelling reaction (fibrocystic breast changes), often accompanied by tightness and tenderness. Typically the tissue feels noticeably better after the period. A single lump that stands out from this, however, remains a reason for an examination.

Inflammation and abscess

During breastfeeding, a blocked milk duct can easily develop into breast inflammation (mastitis): a red, hot, painful hardening with fever and feeling unwell. If an encapsulated collection of pus (abscess) forms, a painful lump remains that needs to be drained. Outside breastfeeding, inflammation is less common; smoking is considered a risk factor. Important: redness that does not settle with treatment must be investigated further, because a rare inflammatory form of breast cancer can look similar. A milk-filled lump during breastfeeding (galactocele), on the other hand, is harmless — questions about medicines while breastfeeding are answered in our guide Medications while breastfeeding.

After a knock, surgery or radiotherapy

After a bruise, a seat-belt injury, breast surgery or radiotherapy, fatty tissue can die and scar (fat necrosis). The resulting lump feels firm and sometimes irregular and can resemble a tumour on imaging — so a tissue sample is often needed. On blood thinners, a palpable bruise is also possible, which recedes over weeks. More on this in our guide Living with blood thinners.

Lumps that are not in the gland at all

Not every bump on the breast is breast tissue. Lipomas, sebaceous or skin cysts sit directly under the skin and are often visible from the outside — more on this in our article on lumps under the skin. In the armpit and the side of the chest, lymph nodes can be felt, which swell with infections or after vaccinations; how to make sense of them is described in our article on swollen lymph nodes. With breast implants, capsular contracture, a defective implant or — very rarely — a late collection of fluid around the implant can cause a lump or swelling; this too needs to be examined.

Breast lumps in men

The most common cause is gynaecomastia: a tender, disc-shaped swelling directly behind the nipple, often on both sides. It is common and temporary in puberty, becomes more common again in older age and is often triggered by medicines, excess weight, liver or hormonal disorders. Breast cancer in men is rare but is often detected late. A one-sided, hard lump that is not centred directly under the nipple, or an inverted nipple, should therefore be checked promptly.

Breast cancer

Breast cancer is the most common cancer in women, and the risk rises with age. Typical is a hard lump with irregular edges that hardly moves and that usually does not hurt at first. Other signs include puckered skin, orange-peel skin, a newly inverted or scaly nipple, bloody discharge, a change in the size or shape of one breast and hard lymph nodes in the armpit. Anyone with several cases of breast or ovarian cancer in the family should mention this at the practice — for a notable family history there are specialised counselling centres. Detected early, breast cancer can be treated well in many cases today.

Self-observation: first clues at home

These observations replace neither a medical examination, imaging nor a diagnosis. They help you get to know your breasts and give the practice precise information.

• The right time: Before the menopause, it is best to feel your breasts a few days after your period, when the tissue is soft. After the menopause the timing does not matter.
• Looking in the mirror: With your arms hanging down, then raised, look at the shape, size, skin puckering, orange-peel skin, redness and the nipples.
• Feeling while lying down: Using the flat of your fingers in small circles, feel the whole breast up to the collarbone, the breastbone and into the armpit, with light, medium and firm pressure.
• Describing the lump: Location as on a clock face (“right, 10 o’clock, three fingers from the nipple”), approximate size, hard or firm-elastic, mobile or fixed, painful or not — and the date.
• The cycle check: Does the lump change after your next period or stay the same? This observation helps the practice — but it is no reason to postpone the appointment.
• The medication check: Note the pill, hormonal coil, hormone replacement therapy, blood thinners and, for men, drugs such as spironolactone, finasteride or testosterone — each with its start date.

According to studies, there is no evidence that regular breast self-examination lowers breast cancer mortality; it is no substitute for early detection screening. But if you know your own breasts, you will notice changes more easily.

Warning signs: when you should not wait

• A new lump after the menopause — regardless of how it feels
• A hard, irregular lump that hardly moves or grows quickly
• Puckered skin, orange-peel skin, a newly inverted nipple or a scaly, sore nipple that does not heal
• Bloody or spontaneous one-sided discharge from the nipple
• Redness or swelling of the breast that does not settle with treatment
• A hard, painless lump in the armpit or above the collarbone
• Any one-sided, hard lump in men
• A lump that can still be felt unchanged after your next period

The treatment pathway: step by step

1. Make an appointment. The first port of call is the gynaecology practice; for men, the GP or urology practice. Beforehand, note when you noticed the lump, whether it has changed, your cycle, illnesses in the family and all your medicines. Tips are in our guide Preparing for a doctor’s appointment.
2. Clinical examination and consultation. The practice examines both breasts, the armpits and the hollows above the collarbones and asks about risk factors.
3. Imaging. In younger women, ultrasound is the first choice; from around 40 or if the findings are unclear, mammography is usually added. MRI is only used in certain situations. The result is often given in BI-RADS categories: 1 and 2 mean unremarkable or benign, 3 probably benign with a follow-up after a few months, 4 and 5 suspicious with a recommendation for a tissue sample.
4. Tissue sample if needed. If the findings are unclear or suspicious, tissue is taken with a hollow needle under ultrasound or X-ray guidance (core needle biopsy), usually as an outpatient and under local anaesthetic. The result is generally available after a few days.
5. Targeted treatment. Simple cysts and confirmed fibroadenomas often need no treatment, possibly follow-up checks. Abscesses are drained and treated with antibiotics. For breast cancer, a certified breast centre plans the treatment; all treatment decisions are made by the treating team together with you.
6. Keep follow-up appointments. If the finding is “probably benign”, the agreed follow-up check is important — put the appointment in your calendar straight away.

The medication angle: hormones, blood thinners and more

Medicines rarely cause a lump themselves, but they do affect breast tissue, examination and diagnosis.

Hormone replacement therapy and contraception

Hormone replacement therapy with estradiol can make glandular tissue denser, encourage cysts and make mammograms harder to interpret. Combined hormone replacement therapy with oestrogen and progestogen also slightly increases the risk of breast cancer, depending on the duration and the preparation — this belongs in the regular weighing of benefits and risks with the practice. A small increase in risk has also been described for the pill, which declines again after stopping. Do not stop hormones on your own because of a lump; raise it at your appointment.

Blood thinners before a biopsy

If you take anticoagulants such as apixaban, rivaroxaban or phenprocoumon, or antiplatelet drugs such as aspirin and clopidogrel, be sure to say so before a core needle biopsy. Whether the medicine is paused briefly is decided by the practice together with the prescriber — not by you alone, because stopping on your own can encourage thrombosis or stroke.

Gynaecomastia caused by medicines

In men, the main triggers of gynaecomastia are spironolactone, the prostate medicines finasteride and dutasteride, anti-androgens for prostate cancer, digitalis, some stomach and psychiatric medicines, as well as anabolic steroids and testosterone. It often recedes after a change of medication if it has not been present for long.

After breast cancer: anti-hormone therapy

Taking tamoxifen or an aromatase inhibitor such as anastrozole after breast cancer protects against a recurrence — provided the tablets are taken regularly over years. New lumps in the operated breast, in the scar or in the armpit should nevertheless be shown to the treatment team promptly.

Painkillers for painful cysts

Ibuprofen or paracetamol can help in the short term with a painful cyst; an anti-inflammatory gel is often better tolerated. According to the package leaflet, over-the-counter painkillers should generally not be taken for more than three to four days in a row without medical advice. If you need them regularly, raise it at your appointment.

Early detection and lowering risks

Benign lumps such as cysts or fibroadenomas cannot be specifically prevented. With breast cancer, some risk factors can be influenced — and above all, early detection can be used:

• Take up early detection — the annual clinical breast examination by a gynaecologist from age 30 and mammography screening every two years for women aged 50 to 75 are covered by statutory health insurance. The information leaflet sent with the invitation explains the benefits and limitations.
• Less alcohol — even small regular amounts increase the risk of breast cancer.
• Exercise and weight — regular exercise and a healthy weight after the menopause lower the risk.
• Use hormones deliberately — hormone replacement therapy during the menopause for as short a time and at as low a dose as the symptoms require, reviewed regularly.
• Know your family history — note breast and ovarian cancer in close relatives and mention it at the practice.

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