To explore the clinical and imaging features of breast fibromatosis (BF).

Clinical data of 39 patients (with a total of 48 lesions) who underwent ultrasound examination and were pathologically confirmed as having BF in the First Affiliated Hospital with Nanjing Medical University from January 2015 to August 2025 were collected. A retrospective analysis was performed on the clinical, ultrasound, mammographic, and MRI data.

The mean age of BF patients was (30.7±9.4) years, and the mean maximum diameter of the lesions was (27.6±17.8) mm. Among the patients who were followed up, 10 cases showed signs of recurrence after surgery, as indicated by ultrasound or MRI. On conventional ultrasound, BF lesions were mainly located in the glandular layer (33/48, 68.8%), and were predominantly of non-mass type (31/48, 64.6%). Most lesions presented as irregular hypoechoic lesions (40/48, 83.4%), with typically homogeneous internal echoes (45/48, 93.8%), clear boundaries (29/48, 60.4%), frequent spiculated or angular margins (42/48, 87.5%), rare calcifications (1/48, 2.1%), and mostly no change in posterior echoes (44/48, 91.7%). The Adler blood flow grade was typically grade 1 (24/48, 50.0%) or grade 2 (20/48, 41.7%). On elastography, BF lesions commonly scored 3 (16/35, 45.7%) or 4 (17/35, 48.6%). On contrast-enhanced ultrasound (CEUS), most BF lesions presented as heterogeneous enhancement (5/6, 83.3%), with absent or minimal internal enhancement and prominent peripheral rim enhancement. Mammographic examination showed that BF mostly appeared as round-like high-density nodules (12/23, 52.2%), while a minority presented as glandular structure retraction (4/23, 17.4%) or irregular masses with spiculation (4/23, 17.4%). A total of 27 lesions underwent MRI, among which 17 were mass-type lesions, most of which exhibited an irregular shape (10/17, 58.8%) and showed homogeneous contrast enhancement (11/17, 64.7%). In contrast, non-mass-type BF (10 lesions) manifested as ill-defined non-mass-like enhancement (10/10, 100%). The time-intensity curves on dynamic contrast-enhanced MRI were predominantly of the progressive type (20/27, 74.1%), and the apparent diffusion coefficient was (1.16±0.22)×10^-3 mm²/s.

BF exhibits certain clinical and imaging characteristics. The three imaging modalities—ultrasound, MRI, and mammography—are complementary to each other, providing important reference information for the diagnosis and treatment of BF.