Purpose: To characterize imaging findings that suggest the benign or malignant histologic nature of phyllodes tumors.
Materials and methods: Clinical and imaging findings were retrospectively reviewed in 46 women with 51 phyllodes tumors (32 benign, 19 malignant) identified at preoperative mammography. Thirty of these tumors were also evaluated with preoperative sonography.
Results: Mammography showed nonspiculated soft-tissue masses in 49 tumors. Four masses contained calcifications; three of these masses were benign. The tumors were 1-20 cm in diameter; tumors 3 cm or larger were statistically significantly more likely to be malignant (P < .004). Sonography showed solid, hypoechoic masses in 28 cases. At sonography, cystic areas were more often seen in malignant than in benign tumors, but the difference was not statistically significant.
Conclusion: There is substantial overlap in the imaging characteristics of benign and malignant phyllodes tumors. A tumor diameter of 3 cm or greater appears to be associated with a higher likelihood of malignancy.