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# Breast fibroadenoma

A breast fibroadenoma is a benign lump made of gland and connective tissue; it is the most common breast lump in teenagers and young women.

Updated 2026-10-29

## Structures involved

Tap one to see what it is and open it in 3D.

- [Mammary gland lobes](https://durgical.com/en/anatomy/mammary-gland/)
- [Breast fat](https://durgical.com/en/anatomy/body-of-breast/)
- [Lactiferous ducts](https://durgical.com/en/anatomy/lactiferous-ducts/)
- [Suspensory ligaments of breast](https://durgical.com/en/anatomy/suspensory-ligaments-of-breast/)

## In histology

- [Breast: ducts, lobules and changes with life stage](https://durgical.com/en/histology/breast-ducts-lobules-and-changes-with-life-stage/)

## In the clinical exam

- [Clinical breast examination](https://durgical.com/en/clinical-exam/clinical-breast-examination/)

## Why it happens

- [Benign vs malignant tumours: the comparison table](https://durgical.com/en/general-pathology/benign-vs-malignant-tumours-the-comparison-table/)
- [Actions of estrogen and progesterone](https://durgical.com/en/physiology/actions-of-estrogen-and-progesterone/)

## What it is

Benign tumour of the breast made of glandular (epithelial) and connective (stromal) tissue. It is the most common breast lump in adolescents and young women.

## Who gets it

Most frequent in women aged about 15 to 35. It often shrinks after menopause. Common worldwide, including in Colombia.

## Causes

- Hormone-dependent overgrowth of the lobule's epithelium and stroma
- Oestrogen sensitivity: may grow in pregnancy or with hormone therapy

## Risk factors

- Young age (adolescence to mid-thirties)
- Female sex
- Hormonal states such as pregnancy
- Immunosuppression (e.g. after transplant) in some reports

## Pathophysiology

A fibroadenoma arises from the terminal duct–lobular unit as a well-circumscribed proliferation of both stroma and ducts. It is hormone sensitive, so it can enlarge in pregnancy and regress after menopause, sometimes calcifying.

## Classification

- Simple fibroadenoma
- Complex fibroadenoma (with cysts, sclerosing adenosis or calcifications)
- Juvenile fibroadenoma (in adolescents, can grow fast)
- Giant fibroadenoma (larger than about 5 cm)

## Symptoms and signs

- Firm, smooth, rubbery, round lump
- Very mobile under the fingers: the «breast mouse»
- Usually painless
- Usually single, sometimes multiple or bilateral

## Red flags

- Rapid growth (consider phyllodes tumour)
- Hard, fixed or irregular lump
- [Skin](https://durgical.com/en/anatomy/skin/) or [nipple](https://durgical.com/en/anatomy/nipple/) changes
- New lump in a woman over 35–40

## Diagnosis

**Clinical**
Smooth, mobile, painless lump in a young woman; diagnosis is confirmed by triple assessment.

**Tests**
Core needle biopsy when imaging is not typical, the lump grows, or the patient is older.

**Imaging**
Ultrasound is the first test in young women: oval, well-defined, homogeneous mass, wider than tall. Mammography in older women may show a smooth mass or popcorn calcifications.

## Differential diagnosis

- Breast cyst
- Phyllodes tumour
- Breast cancer
- Fibrocystic breast changes
- Lipoma

## Goal of treatment

Confirm that the lump is benign, relieve worry, and remove lumps that are large, growing, symptomatic or uncertain.

## Treatment

**Follow-up**
Observation with clinical and ultrasound follow-up for small, typical, biopsy- or imaging-confirmed lesions.

**Surgical**
Surgical excision for large, growing or symptomatic lumps, uncertain histology, or patient preference.

**Procedure**
Minimally invasive options in selected centres, such as vacuum-assisted excision or cryoablation.

## Complications

- Growth during pregnancy
- Distortion of breast shape with giant fibroadenomas
- Missed phyllodes tumour or cancer if not properly assessed

## Prognosis

Excellent. Many stay the same size or shrink; the increase in breast cancer risk is small and mainly with complex fibroadenomas.

## Test yourself

Think of the answer, then tap the question to see it.

## Why is a fibroadenoma called a «breast mouse»?

Because it is very mobile and slips away under the examining fingers.

## Which imaging test is used first for a breast lump in a young woman?

Ultrasound, because dense breast tissue in young women limits mammography.

## What two tissue types make up a fibroadenoma?

Glandular epithelium (ducts) and fibrous stroma, both proliferating within a well-circumscribed mass.

## Which tumour should be suspected if a fibroadenoma-like lump grows quickly?

Phyllodes tumour, a fibroepithelial tumour that can be benign, borderline or malignant.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/breast-fibroadenoma/)

## Related conditions

- [Breast cancer](https://durgical.com/en/conditions/breast-cancer/)
- [Fibrocystic breast changes](https://durgical.com/en/conditions/fibrocystic-breast-changes/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Breast Fibroadenoma](https://www.ncbi.nlm.nih.gov/books/NBK535345/) (StatPearls (NCBI Bookshelf), 2022).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/conditions/breast-fibroadenoma/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/breast-fibroadenoma/