Breast pathology. a H&E stain of the breast biopsy showing fibroepithelial neoplasm composed of glandular epithelium with proliferative hyperplasia on the background of a markedly hypercellular spindle cell stroma. Faint characteristic leaf-like architecture and stromal overgrowth are seen. ×10. b H&E stain of the breast excision showing fibroepithelial stromal hypercellularity, nuclear pleomorphism, >10 mitoses per 10 high-power fields, necrosis, and infiltrative margins consistent with malignant phyllodes tumor. ×40.Malignant Phyllodes Tumor Presenting in Bone, Brain, Lungs, and Lymph Nodes Case Reports in Oncology. Not Altered. CC.