Background: Liposarcoma arising within a phyllodes tumor is extremely rare. To the best of our knowledge, a malignant phyllodes tumor with liposarcomatous stroma diagnosed by fine needle aspiration (FNA) has not been reported before.
Case: A 39-year-old female had a malignant phyllodes tumor with liposarcomatous stroma diagnosed by FNA cytology. Two subtypes of liposarcomatous stroma, including lipomalike differentiated and myxoid, were found in the aspirates. The cytologic findings were very representative of the histologic features.
Conclusion: It is very important to recognize the cytologic features of such rare tumors. An accurate diagnosis preoperatively by FNA permits better therapy planning.