Malignant Phyllodes of Breast

Phyllodes tumors of breast (PTB) have been known to an uncommon and particular disease to handle owing to diagnostic ambiguity and unpredictable clinical outcome. Malignant phyllodes tumors (MPT) are diagnosed when there are marked stromal hypercellularity, atypia, increased mitoses of ≥10/10 HPFs, permeative tumor borders, and stromal overgrowth. The presence of a malignant heterologous element (MHE) places the tumor into the malignant category regardless of other histological features. Excision with negative margins should be achieved for recurrent and malignant phyllodes tumor. An ideal margin width remains to be determined, and may need to be considered in relation to factors such as tumor size and cosmesis. Without the convincing evidence of survival benefit, adjuvant RT has revealed more favorable local control rate compared with observation group. Stromal expression of Twist and Foxc2, epithelial-mesenchymal transition marker, was associated with high tumor grade and poor prognosis. Tumor-associated macrophage drives myoblast differentiation and malignant progression of PTB through a CCL18-driven signaling cascade amenable to antibody disruption. Recent targeted sequencing on PTBs provided insights into the molecular pathogenesis and genetic characterization with potential clinical implications.