Sonographic features of phyllodes tumors of the breast

The aim of this study was to examine the sonographic features of phyllodes tumors of the breast.

Retrospective analysis of prospectively recorded sonographic features was performed on 2268 patients with phyllodes tumors or fibroadenomas during 1995-98. Data from 110 phyllodes tumors (76 benign, 11 borderline, 23 malignant) and 2204 fibroadenomas were analyzed.

The patients with phyllodes tumors were older than the patients with fibroadenoma (mean +/- standard error, 39.7 +/- 1.1 years vs. 33.4 +/- 0.3 years; P < 0.0001). Sixty-four percent of patients with phyllodes tumors were aged 31-50 years, while 68.5% of those with fibroadenoma were aged 21-40 years. Phyllodes tumors were larger than fibroadenomas (5.90 +/- 0.43 cm vs. 1.95 +/- 0.03 cm; P < 0.0001). The ratio of length to anteroposterior diameter of phyllodes tumors was smaller than the ratio of length to anteroposterior diameter of fibroadenomas (1.72 +/- 0.06 vs. 1.89 +/- 0.02; P = 0.0105). Seventy-seven percent of phyllodes tumors were lobulated and 79.5% of fibroadenomas were oval. Lobulated shape of the tumor, heterogeneous echo pattern and absence of microcalcification are significant independent sonographic features in multiple logistic regression analysis to distinguish between phyllodes tumors and fibroadenoma. Benign, borderline and malignant phyllodes tumors displayed no significant differences in tumor size or the ratio of length to anteroposterior diameter.

There is a substantial overlap in the sonographic characteristics between phyllodes tumors and fibroadenoma of the breast. If lobulation and heterogeneous hypoechoic internal echoes are observed and calcifications are absent, a diagnosis of phyllodes tumors should be considered. Sonography cannot distinguish between malignant, borderline and benign phyllodes tumors.