Diagnostic Pathology: Breast 4e delivers an updated, comprehensive diagnostic support tool for anatomic and surgical pathologists who daily are reviewing breast pathology and providing reports to assist in clinical diagnoses and therapeutic decision-making. The chapters in the book provide details on normal breast pathology, details to assist in processing breast specimens, and multiple sections of content on diagnostic patterns, disorders of development, inflammatory lesions, other types of malignancies, and hereditary breast disease. Coverage is also included on unusual presentations of breast lesions. The templated chapters provide a consistent presentation of information that is easily accessed. Over 2,000 images (plus another 800 images in the eBook) are included along with a wealth of unique medical illustrations that illuminate difficult areas of diagnosis. For the 4th edition, updates across several areas are needed, and new overview chapters are added to guide pathologists with differential diagnosis content that assists with identification and diagnosis. Updated details about PD-L1 immunotherapy and HER2 immunotherapy are in place in additional new chapters, along with chapters on the molecular types of breast carcinomas, which together deliver comprehensive details to assist pathologists with identification, diagnosis, and management of disease.