Hyperechoic Appearance of Malignant Phyllodes Tumor with Liposarcomatous Differentiation: A Case Report with Pathologic Correlation

A malignant phyllodes tumor is a rare disease of the breast that usually differentiates into fibrosarcoma, with liposarcomatous differentiation rarely being reported. In general, malignant phyllodes tumors appear as hypoechoic lesions on ultrasonography examination, and have rarely been reported as hyperechoic tumors. Here, we present an extremely rare case of a 62-year-old woman with a palpable mass that was diagnosed as a malignant phyllodes tumor with liposarcomatous differentiation, seen as an unusual hyperechoic mass on ultrasonography. She underwent resection and biopsy, and there was no evidence of tumor recurrence on follow-up examinations. Radiological explanations of this case are presented in detail, and the possible associations between hyperechoic appearance and liposarcomatous differentiation are described. Through our case report, we can identify several potential rare features of various and unpredictable phyllodes tumors.