Section 1. Common Benign Conditions: 1. Periductal Mastitis (duct ectasia), 2. Fat Necrosis, 3. Silicon Mastitis, 4. Pregnancy / Hormone Related Changes, 5. Diabetic Mastopathy, 6. Adenosis, 7. Microglandular Adenosis, 8. Complex Sclerosing Lesions / Radial Scar, Section 2. Proliferative and Pre-invasive Epithelial Lesions: 9. Fibrocystic Changes, 10. Usual Ductal Hyperplasia, 11. Atypical Ductal Hyperplasia, 12. Columnar Cell Changes / Columnar Cell Hyperplasia, 13. Ductal Carcinoma in Situ, 14. Lobular Neoplasia, 15. Papilloma and Papillomatosis, 16. Nipple Papilloma, Section 3. Invasive Carcinomas: 17. Usual Invasive Ductal Carcinoma, or NOS, 18. Infiltrating Lobular Carcinoma, 19. Tubular Carcinoma, 20. Mucinous Carcinoma, 21. Medullary Carcinoma, 22. Metaplastic Carcinoma, 23. Adenoid Cystic Carcinoma, 24. Papillary Carcinoma, Section 4. Proliferative Stromal and Miscellaneous Mesenchymal Lesions: 25. Fibroadenoma, 26. Phyllodes Tumors, 27. Periductal Stromal Tumors, 28. Myofibroblastoma, 29.Angiosarcoma, Section 5. Metastatic Tumors to the Breast: 30. Melanoma, 31. Miscellanea, 32. Lymphoma and Hematopoietic Diseases, Appendix - Overview of Sentinel Lymph Node and Axillay Lymph Node Evaluation