Malignant Phyllodes Tumor with Heterologous Sarcomatous Differentiation: a Case Series and Review of Literature

Malignant phyllodes tumor (MPT) with heterologous sarcomatous differentiation is extremely rare. We reviewed eleven cases of MPT with heterologous sarcomatous differentiation at our institute between 2009 and 2020. Demographic and clinical data were collected from patient records in hospital information system and population-based cancer registry. Each case reviewed retrospectively for the clinical features, prior treatment history, radiological imaging, histopathological and immunohistochemical details, disease stage, outcome and follow-up. On histopathology, four cases showed heterologous liposarcomatous differentiation, three cases showed fibrosarcomatous differentiation, two cases showed osteosarcomatous, and each case had angiosarcomatous and undifferentiated sarcomatous differentiation. Meticulous histopathological sampling along with a correct histopathological diagnosis and subtyping of the heterologous sarcomatous components is essential for planning treatment modality and prognostication of patients, although there are no clear-cut guidelines for surgical management and targeted therapy of these patients due its rarity and paucity of literature.