What is the approach to assessing a breast lump?

Approach to Assessment of Breast Lump

Definition

A true breast mass is a discrete, asymmetrical, three-dimensional lesion distinct from surrounding breast tissue, palpable in the same location across multiple examinations. 1 This differs from generalized nodularity or breast thickening, which represents greater firmness compared to the contralateral breast and is associated with malignancy in approximately 5% of cases. 1

Classification

By Physical Characteristics

• Malignant features: Firm texture, indistinct/irregular borders, fixation to skin or deep fascia, skin dimpling, nipple retraction 1
• Benign features: Mobile, discrete well-defined margins, soft or rubbery texture 1
• Cystic vs. solid: Cannot be reliably distinguished by palpation alone (only 58% of palpable cysts correctly identified by physical examination) 1

By BI-RADS Category (Post-Imaging)

• Category 1-2: Negative or benign 1
• Category 3: Probably benign (<2% malignancy risk) 1
• Category 4-5: Suspicious or highly suggestive of malignancy 1
• Category 6: Proven malignancy 1

Differential Diagnosis

Benign Lesions (Most Common)

• Fibroadenoma: Mobile, well-circumscribed solid mass 2, 3
• Cysts: Simple, complicated, or complex 1
• Fibrocystic changes: Generalized nodularity 2
• Fat necrosis/oil cyst: Post-traumatic or post-surgical 1
• Lipoma: Soft, mobile fatty mass 1
• Intraductal papilloma: May present with nipple discharge 1
• Lactating adenoma: In pregnant/lactating women 4
• Galactocele: In lactating women 4

Malignant Lesions

• Invasive ductal carcinoma: Most common breast cancer 1
• Invasive lobular carcinoma: May present as subtle thickening 1
• Ductal carcinoma in situ (DCIS): May present with microcalcifications 5

History

Mass Characteristics

• Duration: New vs. longstanding 2
• Change over time: Rapid growth, size fluctuation with menstrual cycle 2
• Pain: Most breast cancers are painless, but pain does not exclude malignancy 1
• Skin changes: Dimpling, peau d'orange, erythema 1
• Nipple changes: Retraction, discharge (bloody vs. clear), inversion 1, 5

Red Flags (High Suspicion for Malignancy)

• Fixed, hard mass with irregular borders 1
• Skin dimpling or nipple retraction 1
• Bloody nipple discharge 5
• Palpable axillary or supraclavicular lymphadenopathy 5
• Unilateral, persistent mass not fluctuating with menstrual cycle 2
• Progressive increase in size 1

Risk Factors for Breast Cancer

• Age >40 years (incidence increases significantly) 1
• Family history: First-degree relative with breast/ovarian cancer, known BRCA mutation 6
• Personal history: Prior breast cancer, atypical hyperplasia, LCIS 1
• Reproductive factors: Nulliparity, late first pregnancy, early menarche, late menopause 2
• Hormonal exposure: Prolonged hormone replacement therapy 2
• Prior chest radiation 6

Physical Examination (Focused)

Breast Examination

• Inspect: Asymmetry, skin changes (dimpling, erythema, peau d'orange), nipple retraction/inversion 1, 5
• Palpate systematically: All quadrants of both breasts, document exact location (clock position and distance from nipple) 5
• Mass characteristics: Size (measure in cm), shape, consistency (firm vs. soft), mobility, borders (well-defined vs. irregular) 1, 5
• Skin attachment: Check for fixation to skin or chest wall 1
• Nipple examination: Discharge (express if history suggests), retraction 5

Lymph Node Examination

• Axillary nodes: All levels (low, mid, high axilla) 5
• Supraclavicular nodes: Palpate bilaterally 5
• Infraclavicular nodes: Check for enlargement 5

Contralateral Breast

• Always examine the opposite breast and axilla for comparison and to detect synchronous lesions 5

Investigations

Age-Based Imaging Algorithm

Women ≥40 Years

Initial imaging: Diagnostic mammography (NOT screening mammography) 1, 6

• Standard views: Bilateral mediolateral oblique and craniocaudal views 6
• Radio-opaque marker: Place over palpable finding 6
• Spot compression/magnification views: If initial mammography shows findings requiring characterization 6, 5
• Sensitivity: 86-91% for cancer detection 1, 6

Second step: Targeted breast ultrasound (ALWAYS perform regardless of mammography results) 1, 6, 7

• Rationale: Ultrasound detects 93-100% of cancers occult on mammography 6, 7
• Combined negative predictive value: Mammography + ultrasound >97% 1, 6, 5

Women 30-39 Years

Either diagnostic mammography OR ultrasound as initial study 1, 7

• Ultrasound preferred if: Low clinical suspicion, suspected simple cyst 1
• Mammography indicated if: High clinical suspicion, suspicious ultrasound findings 1

Women <30 Years

Initial imaging: Targeted breast ultrasound ONLY 1, 6, 7

• Rationale: Breast cancer incidence <1% in this age group, denser breast tissue limits mammography sensitivity, avoid unnecessary radiation 1, 6, 7
• Add mammography if: Ultrasound shows suspicious findings OR clinical examination highly suspicious 1, 4

Expected Imaging Findings

Benign Features

• Simple cyst: Anechoic, well-circumscribed, round/oval, imperceptible wall, posterior acoustic enhancement 1
• Complicated cyst: Low-level internal echoes, no solid component, no vascular flow 1
• Fibroadenoma: Oval, circumscribed, homogeneous, wider-than-tall orientation 3
• Lipoma: Fat density on mammography, hyperechoic on ultrasound 1
• Lymph node: Reniform shape, echogenic hilum 1, 7

Suspicious/Malignant Features

• Irregular or spiculated margins 1, 6
• Taller-than-wide orientation 3
• Posterior acoustic shadowing 3
• Microcalcifications (especially pleomorphic or linear branching) 5
• Architectural distortion 1
• Skin thickening or retraction 1

Tissue Diagnosis

Core needle biopsy is MANDATORY for BI-RADS 4-5 lesions 1

• Image-guided preferred: Ultrasound guidance (if visible on US) > stereotactic/DBT guidance 1
• Advantages over FNA: Superior sensitivity, specificity, correct histological grading 1, 7
• Advantages over surgical biopsy: Less scarring, fewer complications, faster recovery, lower cost 1
• Marker clip placement: Allows localization if neoadjuvant therapy needed 1

Concordance assessment is CRITICAL 1

• If benign and image-concordant: Follow-up physical exam ± imaging every 6-12 months for 1-2 years 1
• If benign but image-discordant: Surgical excision required 1
• If atypical hyperplasia, LCIS, ALH: Surgical excision (select patients may be monitored) 1
• If malignant: Proceed to surgical excision per breast cancer guidelines 1

Advanced Imaging (NOT Routinely Indicated)

• MRI, FDG-PEM, Tc-99m sestamibi MBI: Little to no role in initial evaluation of palpable mass 1, 7, 5
• MRI may be considered: Only if conventional imaging is BI-RADS 0 with persistent high clinical suspicion 1

Empiric Treatment

There is NO role for empiric treatment of a palpable breast mass. 1 All palpable masses require imaging evaluation and, if suspicious, tissue diagnosis before any treatment decisions. 1

Management by Imaging Category

BI-RADS 1-2 (Negative/Benign with Clearly Benign Correlate)

• Clinical follow-up only (no imaging follow-up needed) 1, 7
• Examples: Simple cyst, lipoma, hamartoma, benign lymph node, oil cyst 1

BI-RADS 3 (Probably Benign)

• If low clinical suspicion: Physical exam ± ultrasound/mammogram every 6 months for 1-2 years 1
• If clinically suspicious: Core needle biopsy 1
• If size increases or suspicion increases: Surgical excision 1

Simple Cyst Management

• If asymptomatic and concordant with clinical findings: Clinical follow-up, return to routine screening 1
• If symptomatic: Aspiration may be performed 1

Complicated Cyst Management

• Options: Short-term follow-up (BI-RADS 3) OR aspiration 1
• If aspiration performed and fluid is non-bloody with complete resolution: Clinical follow-up 1
• If bloody fluid or residual mass after aspiration: Core needle biopsy 1

Complex Cyst (Cystic and Solid Components)

• Core needle biopsy required 1

Indications to Refer

Immediate Referral to Breast Surgeon/Specialist

• BI-RADS 4-5 on imaging (before or after biopsy) 6
• Confirmed malignancy on core biopsy 6
• Discordance between imaging, biopsy, and clinical findings 6
• Atypical hyperplasia, LCIS, ALH on core biopsy (most cases require surgical excision) 1
• Highly suspicious clinical findings despite negative imaging (physical examination should never be overruled by negative imaging) 1, 5

Urgent Referral (Within Days to Weeks)

• High-risk patients: Strong family history, known BRCA mutation, prior breast cancer 6
• Red flag clinical features: Fixed mass, skin changes, bloody nipple discharge, palpable lymphadenopathy 1, 5

Routine Referral (Can Be Coordinated by Primary Care)

• BI-RADS 3 lesions requiring short-term follow-up 1
• Benign findings confirmed by imaging (primary care can coordinate follow-up) 6

Critical Pitfalls

Imaging Sequence Errors

• NEVER perform biopsy before imaging – biopsy-related changes confuse, alter, obscure, and limit subsequent image interpretation 1, 6, 7, 5
• NEVER rely on mammography alone in women ≥40 years – ultrasound must also be performed regardless of mammography results 6, 7
• NEVER order MRI, PET, or molecular breast imaging as initial evaluation – these have no role in routine palpable mass workup 1, 7, 5

Clinical Assessment Errors

• NEVER assume a palpable mass is benign based on physical examination alone – even experienced examiners show only 73% agreement on need for biopsy among proven malignancies 1, 7
• NEVER let negative imaging overrule highly suspicious clinical findings – any highly suspicious mass should undergo biopsy regardless of imaging 1, 5
• NEVER assume pain indicates benignity – most breast cancers are painless, but pain does not exclude malignancy 1
• NEVER assume cysts can be reliably distinguished from solid masses by palpation – only 58% accuracy 1

Age-Related Errors

• NEVER start with mammography in women <30 years – ultrasound is first-line to avoid unnecessary radiation in this low-risk population 1, 6, 7
• NEVER skip imaging in women <30 years – although cancer incidence is <1%, imaging is still required for proper characterization 1, 6

Biopsy Technique Errors

• NEVER use fine-needle aspiration as definitive diagnosis – core biopsy is superior in sensitivity, specificity, and histological grading 1, 7
• NEVER accept benign biopsy results without confirming image-pathology-clinical concordance – discordance mandates repeat biopsy or surgical excision 1

Follow-Up Errors

• NEVER perform short-term imaging follow-up instead of biopsy for BI-RADS 4-5 lesions – tissue diagnosis is mandatory 1, 5
• NEVER delay diagnostic workup beyond weeks – symptomatic cancers are more aggressive than screen-detected cancers and have poorer prognosis 1

Special Population Errors

• NEVER avoid mammography in pregnant/lactating women if malignancy is suspected – mammography has 90-100% sensitivity in this population and is not contraindicated 6, 4