| Benign | Atypical | Malignant |
Type 1 | Fibroadenomatoid hyperplasia | Flat epithelial atypia |
|
Type 2 | Fibrocystic change Apocrine metaplasia Intraductal papilloma Intracystic papilloma | Atypical ductal hyperplasia | Papillary carcinoma |
Type 3 | Breast abscess Fat necrosis Post-operative seroma Adenomyoepithelioma |
| Papillary DCIS |
Type 4 | Breast abscess Granulomatous mastitis Galactocoele Lymphangioma Foreign body granuloma Myxoid fibroadenoma Benign phyllodes |
| Invasive ductal carcinoma Invasive mucinous carcinoma DCIS Encysted papillary carcinoma Malignant phyllodes Metaplastic breast carcinoma Angiosarcoma |