Classification<unk> s are a fibroepithelial<unk>  composed of an epithelial and a cellular stromal component. They may be considered benign, borderline, or malignant depending on histologic features including stromal cellularity, infiltration at the<unk> 's edge, and mitotic activity. All forms of<unk> s are regarded as having malignant potential. A large series from the M.D. Anderson Cancer Centre reported the incidence of each as benign (58%), borderline (12%), and malignant (30%). Malignant<unk> rs behave like sarcomas and can develop blood-borne metastases. Approximately 10% of patients with<unk> rs develop distant metastases and this can go up to 20% in patients with histologically malignant<unk> rs. The commonest sites for distant metastases are the lung, bone, and abdominal viscera. Rare sites of metastasis, such as to the parotid region, have also been described. They are classified as a fibroepithelial<unk>  by ICD-O, but not by MeSH. Younger women have a higher chance of having a benign<unk> . +Histopathologic classification Benign Borderline Malignant Margin Pushing Infiltrating Stromal atypia Minimal Moderate Severe Mitoses per 10 HPF <5 5 to 9 ≥10 Stromal overgrowth Absent Present
Phyllodes tumor
Fibroadenoma
Intraductal papilloma
Inverted papilloma
Ductal carcinoma in situ
Acinic cell carcinoma
Coloboma
Lobular carcinoma in situ