A 52-year-old woman's screening mammogram shows a 1.2 cm irregular mass with spiculated margins at 2 o'clock in the right breast. No prior imaging is available. According to ACR BI-RADS lexicon, what category should this be assigned?
- A BI-RADS 3 — short-interval follow-up in 6 months
- B BI-RADS 4B — moderate suspicion, tissue biopsy recommended
- C BI-RADS 5 — highly suggestive of malignancy, tissue biopsy required ✓
- D BI-RADS 4A — low suspicion, tissue biopsy recommended
Correct answer: C. BI-RADS 5 — highly suggestive of malignancy, tissue biopsy required
Explanation
A spiculated irregular mass is the single mammographic finding most associated with malignancy (positive predictive value >95%), placing it firmly in BI-RADS 5. BI-RADS 5 indicates findings that are highly suggestive of malignancy and requires histological confirmation. BI-RADS 3 is for probably benign findings (e.g., circumscribed round/oval mass). BI-RADS 4A-C covers low to moderate suspicion lesions. BI-RADS 4B and 4C are for moderately and high-moderately suspicious lesions, but spiculated masses always reach BI-RADS 5.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.