Case ReviewsBorderline Serous Tumors of the Ovary: Diagnostic Challenges and Terminological ConundrumsKolin, David MD, PhD; Clarke, Blaise MBBCh, FRCP(C); Shaw, Patricia A. MD, FRCP(C)Author Information From the Department of Pathology, University Health Network; and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada. Reprints: Patricia A. Shaw, MD, FRCP(C), Department of Pathology, University Health Network, 190 Elizabeth St, Toronto, Ontario, Canada M5G 2C4. E-mail: email@example.com. The authors have no funding or conflicts to declare. AJSP: Reviews & Reports: 7/8 2016 - Volume 21 - Issue 4 - p 165-174 doi: 10.1097/PCR.0000000000000151 Buy Metrics Abstract We present the case of a 47-year-old woman who presented with pelvic discomfort. Pathology showed a serous borderline tumor with multifocal microinvasion, noninvasive tumor implants, and lymph node involvement. Serous borderline tumors are ovarian neoplasms that display branching papillary growth, epithelial stratification, and mild cytologic atypia without destructive stromal invasion. They frequently have mutations in either KRAS or BRAF and are considered to be precursors to low-grade serous carcinoma. Serous borderline tumor nomenclature, natural history, and the significance of histopathologic features such as microinvasion, micropapillary features, and peritoneal implants are all controversial. In this review, serous borderline tumor histopathology, terminology, pathogenesis, prognostic features, and molecular characterization are discussed. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.