Case ReviewsBorderline Mucinous Tumors of the Ovary: Updates in DiagnosisLim, Diana FRCPath, FRCPA*; Oliva, Esther MD†Author Information From the *National University Health System, Singapore; and †Massachusetts General Hospital, Boston, MA. Reprints: Diana Lim, Department of Pathology, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074. E-mail: email@example.com. The authors have no funding or conflicts to declare. AJSP: Reviews & Reports: 9/10 2016 - Volume 21 - Issue 5 - p 214-221 doi: 10.1097/PCR.0000000000000158 Buy Metrics Abstract Mucinous borderline tumors (MBTs) account for approximately 10% of all primary ovarian mucinous neoplasms. These tumors are characteristically heterogeneous in their composition and frequently show a variable admixture of benign and borderline morphologies, and even in some instances, areas of intraepithelial carcinoma and/or small invasive foci. This review discusses the salient clinical and pathological features of MBTs including (1) terminology used to describe tumors with noninvasive carcinoma and stromal microinvasion and the current definitions of these terms, (2) association with mural nodules, (3) immunohistochemical and molecular profile, (4) limitations of frozen section diagnosis, (5) morphological mimics, and (6) recent updates in their treatment and prognosis. Some of the controversial aspects regarding the terminology and diagnosis of these neoplasms will also be explored in this review. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.