Sunday, November 27 | 10:55 a.m.-11:05 a.m. | SSA01-02 | Arie Crown Theater
BI-RADS 3 lesions are seen in nearly 20% of participants after three rounds of screening ultrasound, but they are rarely malignant, according to researchers from Southwoods Imaging Center in Youngstown, OH.In this Sunday morning session, Dr. Richard Barr, PhD, and colleagues will present results from a study they conducted using data from the American College of Radiology Imaging Network (ACRIN) 6666 trial to ascertain the frequency and malignancy rate of BI-RADS 3 ultrasound lesions.
Out of 2,662 trial participants, 519 (19.5%) had 745 BI-RADS 3 lesions, the team found. Of these lesions, 124 (16.6%) were biopsied; six of these biopsied lesions were malignant (representing 4.8% of biopsies and 0.8% of BI-RADS 3 lesions). The six malignant lesions occurred in five (1%) of the 519 participants, and five of the six malignancies were invasive.
What's the bottom line? BI-RADS 3 lesions are common on screening ultrasound, but fewer than 2% are malignant, according to Barr's group.
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)