Phyllodes Tumors of the Breast: A Rare Lesion with Still-Evolving Prognostic Features and Clinical Management

Purpose of Review Phyllodes tumor (PT) of the breast is a rare type of fibroepithelial lesion classically presenting in 40–50-year olds. PTs can present a diagnostic challenge with histologic, imaging, and genetic features significantly overlapping other breast lesions, particularly fibroadenomas (FAs). Recent Findings PTs are subclassified as benign, borderline, or malignant based on histologic features, with a 10–30% malignancy rate, of which 25–30% will metastasize. Lesion characteristics and histology from image-guided biopsy are used to help distinguish between benign or malignant PTs and other fibroepithelial lesions. Surgical excision is often performed due to PT’s potential for recurrence, rapid growth, and metastasis. However, the state of management is evolving, with conflicting reports presented in the literature regarding the roles of local excision, mastectomy, and radiation treatment. Summary Here we present the histologic, imaging, genetic characteristics, and clinical management options of PTs, highlighting features to help the radiologist distinguish between PTs and FAs, such as the presence of a leaf-like stromal pattern on histology, rapid growth, and unique imaging characteristics.