Diagnostic algorithm for palpable breast abnormalities in women less than 30 years of age

US: ultrasound; BI-RADS: Breast Imaging-Reporting and Data System; FNA: fine needle aspiration; CNB: core needle biopsy.
* Palpable lesions may also undergo needle sampling. However, the US-first approach illustrated here is preferred.
¶ BI-RADS 4C and 5 lesions require surgical evaluation prior to percutaneous biopsy. The presence and size of a mass may influence the choice of biopsy method.
Δ Not all high-risk benign lesions require excision; practices also vary between excision and observation for lesions with atypia. Refer to UpToDate topic on atypia and lobular carcinoma in situ for details.