During the past 20 years, we have witnessed unprecedentedly fast developments in breast pathology and management of breast diseases, including but not limited to the molecular classification of breast cancer and multigene profiling assays and personalized therapies for patients with breast cancer, as well as the management of high-risk lesions diagnosed on core needle biopsies with a greater emphasis on radiologic-pathologic correlation. In addition, the emergence of artificial intelligence (AI) in pathology has created tremendous opportunities for improving diagnostic accuracy and development of prognostic and predictive biomarkers in breast cancer. In view of the Archives’ mission to represent the interests of the public, patients, and pathologists by helping laboratorians keep current with the quickly evolving field of breast pathology, we believe it is of utmost importance for pathologists to have access to the up-to-date, intelligible, and evidence-based data necessary to their successful practice.

In this special section, we compiled a series of 5 review articles (Part I and Part II) written by the thought leaders in this complex field. In the first article, Yueping Liu, MD, and colleagues provide an updated review of AI in breast pathology. They discuss current challenges and the potential use of AI in diagnosing and grading breast carcinomas, identifying metastatic carcinoma in axillary lymph nodes, quantitatively assessing breast cancer biomarkers to predict prognosis and response to therapy, and even predicting potential molecular changes within the neoplastic cells. Liu and colleagues emphasize that AI has tremendous potential to improve the accuracy of histopathologic diagnosis, reduce pathologists’ daily workload, and provide valuable prognostic and predictive information. The second article, by Edward T. Richardson, MD, PhD, and colleagues, examines recent advances in understanding the pathogenesis and novel diagnostic tools of salivary gland–like carcinomas of the breast, a subtype of triple-negative breast cancer characterized by a more favorable prognosis than most triple-negative carcinomas. They describe the clinical, histologic, immunophenotypic, and molecular features of these tumors in comparison with their salivary gland counterparts and also explore benign salivary gland–like tumors of the breast. The third article by Liza M. Quintana, MD, and Laura C. Collins, MD, is on diagnostic pitfalls in breast pathology with an emphasis on core biopsies. The authors discuss the pitfalls in diagnosing benign and malignant lesions in core biopsies and provide morphologic clues and guidance to the appropriate use and interpretation of immunohistochemical markers.

Beginning Part II of this special section, Qinqing Ding, MD, PhD, and colleagues provide an overview of common applications of immunohistochemical (IHC) stains for diagnosing invasive and noninvasive breast lesions, including benign and malignant spindle cell lesions. They discuss the strengths and limitations of IHC stains and provide evidence and their experiences in using these IHC stains to render accurate diagnoses of these lesions. The final article in the special section, by Gulisa Turashvili, MD, PhD, and Xiaoxian Li, MD, PhD, provides a comprehensive overview of inflammatory lesions of the breast with etiopathogenesis, clinical, radiologic, and pathologic features focusing on a practical approach for differential diagnosis, treatment, and prognosis. They emphasize that pathologists have a unique opportunity to play an essential role in patient management when accurately diagnosing clinically significant entities, such as cystic neutrophilic granulomatous mastitis, immunoglobulin G4 mastitis, or squamous metaplasia of lactiferous ducts.

We hope the readers will enjoy this collection of review articles discussing some of the important and updated topics in neoplastic and nonneoplastic breast pathology. The information presented herein will be helpful to a large audience, including practicing pathologists, pathology trainees, breast imagers, oncologists, and surgeons, as well as physicians from other specialties.

We sincerely thank Archives of Pathology & Laboratory Medicine Editor in Chief Alain C. Borczuk, and Managing Editor Katie Giesen for providing the opportunity for and the outstanding support during the publication of these articles.

Competing Interests

The authors have no relevant financial interest in the products or companies described in this article.