Evaluation of a Breast Lump
Begin with ultrasound as the first imaging study if the patient is under 30 years old, or diagnostic mammography if 40 years or older, followed by ultrasound regardless of mammography results. 1, 2
Age-Based Initial Imaging Approach
The initial imaging strategy depends critically on patient age:
Women <30 years: Proceed directly to targeted breast ultrasound without mammography, as breast cancer incidence is <1% in this population and unnecessary radiation exposure should be avoided 1, 2, 3
Women 30-39 years: Either diagnostic mammography or ultrasound is appropriate as the initial study, depending on clinical suspicion 1, 2
Women ≥40 years: Diagnostic mammography is the first-line imaging study, detecting 86-91% of breast cancers in this age group 1, 2
Critical Sequencing Rule
Never perform biopsy before completing imaging evaluation. Biopsy-related changes will confuse, alter, obscure, and limit subsequent image interpretation 1, 3. Complete the full imaging workup first.
Comprehensive Imaging Workup for Women ≥40 Years
After diagnostic mammography:
Always perform targeted breast ultrasound regardless of mammography results, as ultrasound detects 93-100% of cancers that are occult on mammography 1
Place a radio-opaque marker over the palpable finding during mammography 1
Consider spot compression views with or without magnification to evaluate mass margins and determine if findings are truly suspicious 1
The combined negative predictive value of mammography and ultrasound is >97% when both are benign 1
Management Based on Imaging Results
Suspicious Findings (BI-RADS 4-5)
Proceed directly to image-guided core biopsy (ultrasound-guided or stereotactic), as core biopsy is superior to fine-needle aspiration in sensitivity, specificity, and correct histological grading 4, 1, 3. Core biopsy also allows evaluation of tumor receptor status 4.
Probably Benign Findings (BI-RADS 3)
Short-interval ultrasound follow-up is reasonable for masses with benign features (oval/round shape, well-defined margins, homogeneous echogenicity, parallel orientation) if clinical examination also suggests benign etiology 4
The likelihood of malignancy is particularly low in young women—only 0.3% (1 of 357 patients) younger than 25 years with probably benign features were subsequently diagnosed with malignancy 4
Consider immediate biopsy instead of follow-up for high-risk patients, those awaiting organ transplant, patients with known synchronous cancers, those trying to conceive, or when extreme patient anxiety warrants definitive diagnosis 4
Clearly Benign Findings (BI-RADS 1-2)
If imaging demonstrates a clearly benign entity (simple cyst, benign lymph node, lipoma, hamartoma), return to clinical follow-up only—no further imaging or biopsy is needed 1, 3
Negative Imaging with Suspicious Clinical Examination
If physical examination is highly suspicious but mammography and ultrasound are negative, tissue sampling with core biopsy or surgical biopsy is still warranted. Physical examination findings should never be overruled by negative imaging 4, 3. Even experienced examiners show only 73% agreement on the need for biopsy among proven malignancies 1.
What NOT to Do
Do not order MRI, PET, or molecular breast imaging as initial evaluation—these have no role in the workup of a palpable mass 4, 1, 3
Do not rely on mammography alone to determine if biopsy is needed—ultrasound must also be performed 1
Do not delay imaging evaluation—physical examination alone is unreliable 1
Special Populations
Pregnant or lactating women: Ultrasound is often chosen first due to tissue density, but mammography is not contraindicated during pregnancy or lactation and should be performed if malignancy is suspected, as it has 90-100% sensitivity for detecting malignancy in this population 1.