Malignant phyllodes tumor


A biopsy and subsequent wide local excision was undertaken.

  • Procedure: Ultrasound-guided biopsy of left breast mass. Diagnosis: Fibroepithelial lesion consistent with phyllodes tumor, high-grade.  Immunohistochemical study: High Ki67 proliferation index (about 60-70%) in the mesenchymal component of the tumor. CD10 is positive in the myoepithelial layer of the epithelial component, but negative in the mesenchymal component.  CD117 is focally positive in the epithelial and mesenchymal components. CD34 is negative in the mesenchymal component.  P53 is noncontributory.  The morphological features (fragmented tissue, periductal hypercellularity, atypical spindle cells with focal pleomorphism, presence of about five (5) abnormal mitoses per 10 high-power field, presence of apoptotic cells) associated with this immunophenotype (especially high Ki67) are in favor of phyllodes tumor, high-grade.  Wide margin excision of this tumor is recommended.
  • Procedure: Wide local excision of left breast mass. Tumor site: Left breast. Tumor size: 5 cm in diameter. Histologic type: Phyllodes tumor (phyllodes sarcoma). Histologic grade:  High-grade (phyllodes sarcoma). No heterogeneous component identified. Mitotic rate:  >50/10 high-power field. Necrosis: Present (10%). Margins: Uninvolved by the tumor. Lymphovascular invasion: Not identified. Additional pathologic findings: Presence of intraductal hyperplasia adjacent to the tumor without atypia, DCIS or malignancy. Pathologic stage classification: pT2NxMx.


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