On dynamic contrast-enhanced breast MRI, a 10 mm enhancing mass shows slow initial enhancement (50% signal increase in the first 2 minutes) followed by persistent progressive enhancement on delayed phases (type I kinetic curve). This pattern is most consistent with:
- A Invasive ductal carcinoma
- B Fibroadenoma ✓
- C Invasive lobular carcinoma
- D Ductal carcinoma in situ
Correct answer: B. Fibroadenoma
Explanation
A type I kinetic curve on breast MRI shows slow initial enhancement with persistent progressive enhancement on delayed phases. This pattern is strongly associated with benign lesions, particularly fibroadenomas. Type III curve (rapid enhancement with washout) is the most specific for malignancy. Type II curve (rapid enhancement with plateau) is intermediate. While some malignancies can show type I kinetics, the pattern is most characteristic of benign proliferative tissue.
Reference: ACR BI-RADS Atlas, 5th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.