Ovarian Mucinous Neoplasms: An Integrated Clinicopathologic Perspective

Context.— Primary ovarian mucinous neoplasms represent a highly heterogeneous group of tumors. Despite being relatively common among ovarian tumors, they pose diagnostic challenges even for experienced gynecologic pathologists based on morphologic assessment, which serves as the primary means of classification and is intrinsically subject to substantial interobserver variability. Patients with low-stage disease generally have excellent outcomes, but infiltrative growth is associated with increased risk and high-stage disease is typically both aggressive and resistant to traditional therapy. Objective.— To review diagnostic criteria for classification of mucinous tumors, highlight recent updates on grading and ancillary testing, and discuss ongoing challenges of classification as they relate to clinical management. Data Sources.— Published peer-reviewed literature and personal experience of the authors. Conclusions.— Primary ovarian mucinous neoplasms are frequently encountered in routine gynecologic pathology practice; however, their classification remains problematic. Much of the difficulty surrounding their diagnosis stems from their incredible spatial heterogeneity, which is confounded by frequent discordance between gross and histologic findings. One is faced with an even greater challenge during intraoperative assessment, because it drastically alters surgical management in real time, with limited sampling. The recent adoption of growth pattern–based grading may ultimately serve as a means of simplifying the approach to these elusive tumors for patients who present with low-stage disease. For those presenting with high-stage disease, ancillary testing to guide individualized therapy remains largely rooted in pan-tumor strategies, and study of potential biomarker-based approaches is ongoing.