Risk Stratification of Fibroepithelial Breast Lesions: Clinical and Ultrasound Features Associated with Fibroadenoma and Phyllodes Tumors.

Abstract

Fibroepithelial lesions (FELs) diagnosed on core needle biopsy frequently prompt surgical excision because of the diagnostic uncertainty between fibroadenomas (FAs) and phyllodes tumors (PTs). We sought to identify clinical and ultrasound features associated with FEL subtypes to inform individualized surgical decision-making. We performed a retrospective review of women diagnosed with FELs on core biopsy between 2003 and 2024 who underwent diagnostic ultrasound and surgical excision. Clinical and sonographic features were compared between (1) FAs and PTs and (2) benign versus borderline/malignant PTs. Predictors were assessed using univariate and multivariable logistic regression. Among 694 FELs in 673 women, 405 (58.4%) were FAs and 289 (41.6%) were PTs. PTs occurred in older patients (median 40 vs. 32 years), with larger tumors (2.4 vs. 1.9 cm) and higher body mass index (BMI; 25.8 vs. 23.5 kg/m²; all p < 0.001). On multivariable analysis, increasing age (odds ratio [OR] 1.045; 95% confidence interval [CI] 1.027-1.064), increasing BMI (OR 1.036; 95% CI 1.006-1.067), larger tumor size (OR 1.460; 95% CI 1.290-1.672), and non-circumscribed margins (OR 0.688; 95% CI 0.492-0.961) independently predicted PTs. On multivariable analysis of 289 PTs, tumor size (OR 1.363; 95% CI 1.179-1.616) and postmenopausal status (OR 3.052; 95% CI 1.141-8.258) were independently associated with borderline/malignant subtypes (n = 78). Younger, premenopausal patients with normal-range BMI and small, circumscribed tumors demonstrate features strongly associated with fibroadenomas, whereas increasing size, BMI, and postmenopausal status identify higher-risk PTs. These findings support integrating clinical risk stratification into shared decision-making for the management of indeterminate FELs.