Imaging features of primary breast sarcoma.

Objective: This purpose of this study is to describe the imaging findings in patients who presented with a diagnosis of primary breast sarcoma.
Materials and Methods: A search was performed of the pathology database at a single institution for patients with a histopathologic diagnosis of primary breast sarcoma or pure sarcomatoid carcinoma and who underwent preoperative mammography, sonography, or MRI. Patients with malignant phyllodes tumors were excluded. The imaging studies were retrospectively reviewed using the American College of Radiology BI-RADS lexicon. We documented clinical presentation, histopathologic characteristics, axillary nodal status, and the presence of distant metastases.
Results: Twenty-four women were included in the study; their mean age was 56 years (range, 21-86 years), and the mean tumor size was 6.1 cm (range, 0.9-15 cm). Only one tumor was identified in each patient. The predominant mammographic finding was a noncalcified oval mass with indistinct (9/14 [64%]) margins. Sonography most commonly revealed an oval (19/22 [86%]) solid mass with indistinct margins (17/22 [77%]). The masses were frequently hypoechoic (18/21 [86%]) and hypervascular (17/20 [85%]) and had posterior acoustic enhancement (13/21 [62%]). MRI showed a round or oval T2-hyperintense mass with irregular margins in four of five (80%) patients, and inhomogeneous enhancement was most common (3/4 [75%]).
Conclusion: Primary breast sarcoma has imaging features that are not typically seen in infiltrating ductal carcinoma. A large oval hypervascular mass with indistinct margins should raise the suspicion for a primary breast sarcoma and prompt biopsy.