Malignant phyllodes tumor of the breast with heterologous osteosarcomatous and pleomorphic liposarcomatous differentiation: a rare case report and literature review.

Malignant phyllodes tumors (MPTs) of the breast account for approximately 8% to 20% of all phyllodes tumors (PTs) and represent a rare but clinically significant subtype of breast malignancy. Diagnosis is based on the histologic criteria of increased stromal cellularity, stromal overgrowth, cytologic atypia, elevated mitotic activity, and infiltrative tumor margins. MPTs may be associated with malignant heterologous elements, although most tumors exhibit a single component. The coexistence of two or more heterologous components is extremely rare. Herein, we report a case of malignant phyllodes tumor in a 60-year-old female, characterized by heterologous components of osteosarcoma and pleomorphic liposarcoma. We detail the treatment and outcomes, and present a literature review summarizing cases with two or more heterologous elements. This study aims to expand clinical understanding, elucidate the prognostic significance of heterologous component types, and inform the diagnosis and treatment of this rare entity.