Breast lump and triple assessment

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

A breast lump is a presentation, not a diagnosis. Age, pregnancy, pain, mobility and family history change probability but cannot safely rule cancer in or out. History covers duration, growth, cycle relation, pregnancy and lactation, trauma, infection, nipple change, prior imaging, operations, hormones and familial cancer. Examination compares both breasts and nodal basins, recording the target precisely. A normal examination does not cancel investigation of a patient-localised persistent abnormality.

Imaging is selected by age and context. Targeted ultrasound distinguishes solid from cystic disease and assesses axillary nodes. Mammography reveals masses, distortion and calcification across both breasts, with tomosynthesis or magnification views when useful. Pregnancy begins with ultrasound and uses mammography when the answer is necessary with appropriate technique; ionising-radiation concern should not create diagnostic delay. MRI answers selected staging and problem-solving questions rather than replacing initial mammography and ultrasound.

Tissue completes triple assessment when imaging or examination is suspicious or indeterminate. Image-guided core biopsy is generally preferred for a solid breast target. Suspicious nodes may undergo ultrasound-guided core or FNA. Pathology uses B categories and may require immunohistochemistry or receptor testing after malignancy is established. A result must be judged against the exact target: benign tissue from a technically missed or unrepresentative area is not a benign diagnosis of the lesion.

Urgent presentations sit alongside the cancer pathway. Lactational mastitis commonly improves with effective milk drainage and appropriate antibiotics, but a collection needs ultrasound-guided aspiration or catheter drainage. Inflammatory breast cancer can resemble infection, usually with rapid diffuse skin oedema and no response to antibiotics. Persistent or recurrent inflammation therefore returns to triple assessment, including skin punch or breast core biopsy when dermal lymphatic involvement is suspected.

Key points

Triple assessment means clinical history and examination, appropriate breast imaging and pathological sampling when indicated; diagnostic confidence depends on concordance between all three components.
Refer adults meeting suspected-cancer criteria promptly. A painful lump can still be malignant, and young age or pregnancy does not remove the need for assessment.
Ultrasound is usually the first imaging test in younger patients and during pregnancy or lactation; mammography is central from the usual screening-age range and is commonly combined with targeted ultrasound.
Core-needle biopsy is the preferred tissue test for a suspicious solid lesion because it preserves architecture and permits invasive, receptor and subtype assessment; FNA has selected roles, especially nodes or cysts.
MRI is not routine first-line imaging for an uncomplicated lump; use it for a defined question such as occult primary, implant integrity or extent in selected known cancer.
A simple cyst with complete symptom resolution may need no tissue, while a complex cystic-solid lesion, bloody aspirate or residual mass needs further imaging and biopsy.
A benign pathology label is safe only when it explains the examination and imaging. Discordance requires radiology–pathology review and repeat targeted sampling or excision.
Treat mastitis promptly, but drain an abscess rather than relying on antibiotics alone and reassess persistent non-lactational or atypical inflammation for inflammatory cancer.
Document size, clock-face position, distance from nipple, skin and nipple findings and nodes so that clinical, imaging and biopsy targets can be matched precisely.
Communicate results through a clear pathway: benign concordant discharge or surveillance, uncertain lesion review, and malignant breast MDT staging and treatment.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Benign epithelial and stromal lesions

Fibroadenoma, cyst, duct ectasia, papilloma and hormonally responsive nodularity account for many breast lumps, with probability varying by age and reproductive state.

Inflammation and trauma

Lactational milk stasis, bacterial mastitis, abscess, fat necrosis and postoperative seroma can produce tender or firm masses that sometimes mimic malignancy clinically and radiologically.

Primary breast malignancy

Invasive carcinoma, ductal carcinoma in situ and less common lobular, inflammatory, phyllodes, lymphoma or metastatic lesions may present as breast or nodal abnormalities.

Inherited and exposure-related risk

Age, family history, pathogenic susceptibility variants, prior thoracic irradiation, dense breasts, alcohol and prolonged oestrogen exposure alter pre-test probability but never diagnose a lump.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Mass effect changes local architecture
A benign expansile lesion displaces tissue, whereas infiltrating carcinoma produces desmoplasia, architectural distortion, ligament tethering and sometimes skin or nipple retraction.
2
Ductal processes cause discharge
Papilloma, duct ectasia, infection and malignancy can disrupt or distend a duct, producing unilateral or multiduct fluid with different colour and risk patterns.
3
Inflammation produces oedema
Infection increases vascular permeability and recruits neutrophils, while dermal lymphatic tumour emboli obstruct drainage and create non-infective erythema and peau d’orange.
4
Malignant cells reach regional nodes
Invasive cancer enters lymphatic channels and commonly spreads to axillary, internal mammary and supraclavicular basins, making nodal examination and imaging part of assessment.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Suspicious solid mass

Hardness, irregular margin, fixation, architectural tethering or associated nipple and skin change increases malignant probability, but absence does not exclude cancer.

Cystic lesion

A smooth fluctuant tender lump may fluctuate with the cycle; ultrasound is needed when it persists, recurs or is not clinically unequivocal.

Infection or abscess

Focal heat, erythema, tenderness, fever and fluctuation suggest mastitis with possible collection, particularly during lactation or periductal disease.

Inflammatory cancerRed flag

Rapid diffuse enlargement, erythema, peau d’orange and breast heaviness without convincing sepsis or antibiotic response requires urgent tissue diagnosis.

Pathological nipple finding

Spontaneous unilateral single-duct blood, new inversion, ulceration or persistent eczematous nipple change is more concerning than bilateral expressed milky discharge.

Regional nodal disease

A hard rounded axillary or supraclavicular node, loss of normal mobility or suspicious ultrasound cortex may represent breast-cancer metastasis.

Red flags requiring action

A hard irregular fixed breast mass, skin tethering, nipple distortion or a suspicious axillary or supraclavicular node requires urgent cancer-pathway assessment.
Diffuse erythema, oedema and peau d’orange affecting a substantial part of the breast can represent inflammatory cancer even without a discrete lump.
Bloody unilateral single-duct discharge, new nipple inversion, Paget-like eczema or nipple ulceration needs specialist assessment.
A breast abscess with fever, hypotension, immunosuppression, pregnancy, implant, skin necrosis or failed oral therapy needs urgent escalation.
Pregnancy or lactation must not be used to explain away a persistent mass; ultrasound and tissue sampling can be performed safely when indicated.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
First-line clinical breast and nodal examinationFirst stepFirst line
Why
Localise the abnormality and identify skin, nipple, chest-wall and regional-node findings that determine imaging urgency.
Interpretation and limitations
Record side, quadrant or clock position, size, mobility and distance from nipple; clinical P grading contributes to triple-assessment concordance but cannot replace imaging.
02
First-line targeted breast ultrasoundFirst line
Why
Differentiate cystic and solid lesions, evaluate margins and vascularity and assess axillary nodes without ionising radiation.
Interpretation and limitations
Use as initial imaging in younger and pregnant patients and as an adjunct at any age; assign a standard imaging category and biopsy suspicious solid or complex targets.
03
Diagnostic bilateral mammography
Why
Detect mass, distortion, asymmetry and microcalcification and look for multifocal, contralateral or occult disease.
Interpretation and limitations
Use age- and context-appropriate projections, tomosynthesis or magnification; a mammographically occult palpable lesion still needs targeted ultrasound and concordance review.
04
Preferred image-guided core biopsyPreferred
Why
Provide architecture and sufficient tissue to classify a suspicious solid lesion and establish invasive disease.
Interpretation and limitations
Target the imaging abnormality precisely and place a marker when appropriate; B1 or benign B2 tissue is inadequate reassurance if imaging remains U4, U5, M4 or M5.
05
Node sampling
Why
Confirm regional metastasis before surgery and help select sentinel-node, targeted or axillary management.
Interpretation and limitations
Ultrasound-guided core or FNA is chosen by local protocol; a negative sample may need repeat when morphology and pre-test probability remain highly suspicious.
06
Breast MRI for a defined indication
Why
Assess extent, occult primary, implants or selected high-risk and treatment-planning questions when conventional assessment is insufficient.
Interpretation and limitations
High sensitivity produces additional benign enhancement; second-look ultrasound and image-guided biopsy are required before changing definitive surgery from MRI alone.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Fibroadenoma or phyllodes tumour

A mobile circumscribed solid mass is often fibroadenoma, but rapid growth, older age or stromal atypia raises phyllodes and requires core diagnosis and excision planning.

Simple or complicated cyst

A fluctuant or tender lesion may be fluid filled; ultrasound distinguishes a simple cyst from complex solid or vascular components that need sampling.

Mastitis and abscess

Pain, warmth, erythema and fever support infection, but non-lactational, recurrent or non-resolving inflammation requires investigation for diabetes, fistula and underlying cancer.

Fat necrosis

Trauma, surgery or radiotherapy can cause oil cyst, calcification and a hard tethered lump; imaging and core biopsy may be needed because appearances overlap carcinoma.

Breast carcinoma

Irregular fixation, distortion, abnormal nodes or suspicious imaging raises invasive disease, although early cancer may remain smooth, mobile or clinically subtle.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01New lumpComplete concordant triple assessmentFirst stepA patient reports a persistent breast or axillary lump or examination finds a focal abnormality.

1Take a focused cancer, reproductive, infection, trauma and family history and examine both breasts, nipples and regional nodes, documenting the target accurately.
2Arrange age- and context-appropriate mammography and targeted ultrasound through the symptomatic breast service rather than ordering isolated tests without review.
3Obtain image-guided core tissue for suspicious or indeterminate solid findings and close the loop only after clinical, imaging and pathology results are demonstrably concordant.

02DiscordanceDo not accept a mismatched benign resultCore pathology appears benign but examination or imaging remains suspicious or the sampled target is uncertain.

1Review the images, needle position, specimen radiograph when relevant and pathology together at the breast multidisciplinary or radiology–pathology meeting.
2Repeat ultrasound-, stereotactic- or MRI-guided core or vacuum-assisted biopsy of the correct target, or arrange diagnostic excision when percutaneous sampling cannot resolve concern.
3Explain that the issue is sampling confidence rather than a proven cancer and maintain urgent follow-up until a concordant diagnosis is reached.

03Inflamed breastTreat infection and prove resolutionPain, erythema, fever or a possible breast collection is present.

1Assess sepsis, pregnancy or lactation, diabetes, smoking, immune status, implant and recurrence, and obtain ultrasound promptly when abscess is possible.
2Support effective milk drainage when lactating, start appropriate antibiotics and drain a collection with image-guided aspiration or catheter plus culture rather than antibiotics alone.
3Re-examine after treatment and return persistent, recurrent or non-lactational change to urgent triple assessment, adding skin or breast core biopsy when inflammatory cancer is possible.

04ResultRoute by diagnosis and concordanceClinical, imaging and tissue results are available.

1Discharge or provide defined surveillance for a benign concordant diagnosis with safety-net features and a route back for growth or new symptoms.
2Discuss B3 or uncertain lesions in the specialist MDT and choose vacuum excision, surgical excision or surveillance according to lesion type, sampling adequacy and upgrade risk.
3DefinitiveFor malignancy, communicate the result with support, complete receptor and staging work-up proportionately and refer to the breast cancer MDT before definitive treatment.

Key medicines and prescribing safety2 treatments · regimens, roles and cautions

Treats likely penicillin-sensitive staphylococcal mastitis while milk drainage and assessment for a collection continue.

Flucloxacillin for uncomplicated bacterial mastitis

A common adult regimen is flucloxacillin 500 mg orally four times daily for 10 to 14 days, adjusted to local antimicrobial guidance, allergy, culture, severity and renal or hepatic context.

Do not use antibiotics as sole treatment for an abscess or as repeated empirical therapy for non-resolving inflammatory change; avoid in immediate penicillin allergy and review urgently if systemic illness worsens.

Provides analgesia during benign inflammatory, cyst aspiration or biopsy pathways without obscuring the need to investigate a persistent lump.

Paracetamol for breast pain

Give 500 mg to 1 g orally up to four times daily when required, at least 4 hours apart and to a usual maximum of 4 g in 24 hours; use a lower ceiling when clinically indicated.

Account for all combination products and reduce dose in low body weight, malnutrition, alcohol dependence or liver impairment; pain relief must not be interpreted as diagnostic reassurance.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Delayed cancer diagnosis

Attributing a persistent lump to age, pregnancy, pain or a previous benign result can allow local and nodal progression before definitive tissue diagnosis.

Abscess and systemic infection

Untreated mastitis may form a drainable collection, fistula or recurrent periductal infection and can progress to sepsis in vulnerable patients.

Sampling and imaging discordance

A benign core from the wrong target can falsely reassure when clinical or radiological features remain suspicious, requiring repeat or vacuum-assisted sampling.

Procedure morbidity

Biopsy and drainage can cause pain, bruising, infection, pneumothorax at deep targets or implant injury, mitigated by image guidance and aftercare.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Track the patient-localised lump until clinical and imaging teams agree that the correct target has been assessed; a missed target is not a negative test.
After biopsy, review bleeding, haematoma, infection, wound and result communication and ensure every pathology result has a named clinician and action.
For a benign concordant mass, provide return criteria for growth, fixation, skin or nipple change, new nodes and persistent focal symptoms.
After mastitis or abscess treatment, document resolution clinically and by repeat ultrasound when a collection or residual mass was present.
For B3 lesions, record the planned vacuum excision, surgery or imaging surveillance interval and confirm attendance rather than leaving open-ended follow-up.
Audit triple-assessment discordance, repeat-biopsy and missed-appointment cases because failures occur most often at transitions between tests.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Concordance is the safety mechanism

Three individually reassuring components are not enough if they describe different targets; the clinical lump, image and specimen must represent the same process.

Pain does not exclude cancer

Tenderness favours inflammation or cyst but some cancers hurt through rapid growth, skin involvement or coincidental cyclical pain.

Pregnancy changes sequence, not urgency

Ultrasound leads and biopsy is feasible; necessary mammography can follow, while gadolinium MRI and staging choices require specific pregnancy risk assessment.

Cyst aspiration can diagnose and treat

Complete disappearance of a simple cyst with non-bloody fluid is reassuring, whereas a residual mass, recurrence or bloody aspirate changes the pathway.

Adult lateral nodes need a primary search

Axillary adenopathy may be reactive, lymphoma, melanoma or non-breast metastasis, so tissue and complete examination should not assume breast origin.

Inflammatory cancer may lack a mass

Dermal lymphatic obstruction can create rapid diffuse change without a dominant lump, making skin and parenchymal sampling crucial when infection does not fit.

11Common pitfallsFrequent interpretation and management errors.

01
Reassuring from mobility, tenderness, young age, pregnancy or a negative family history without completing assessment.
02
Ordering mammography alone for a palpable lesion and ignoring a normal result despite persistent clinical localisation.
03
Accepting benign core pathology when the needle sampled a different area or imaging remains suspicious.
04
Using MRI as a routine first test and acting on additional enhancement without tissue confirmation.
05
Treating an abscess with antibiotics alone instead of drainage and culture.
06
Continuing repeated antibiotics for peau d’orange that lacks systemic infection or fails to resolve.
07
Excising an uncertain lesion before specialist image–pathology review when vacuum-assisted diagnosis could be more appropriate.
08
Failing to name who will communicate the result and complete the next step.