62 Biomedical Journal of Indonesia Journal Homepage: https://bji-fk.ejournal.unsri.ac.id Biomedical Journal of Indonesia Vol 9 Issue 3 2023 Mucinous Tumors of The Ovary: Current Diagnosis in Histopathological Perspective Florinda Ilona 1* , Dyah Ayu Woro 1 , Reza Aditya Digambiro 1 1 Department of Anatomical Pathology, Faculty of Medicine, Universitas Trisakti, Jakarta, Indonesia ARTICLE INFO Keywords: Mucinous tumor Ovary Histopathological Corresponding author: Florinda Ilona E-mail address: florinda.ilona@trisakti.ac.id All authors have reviewed and approved the final version of the manuscript. https://doi.org/10.32539/BJI.v9i3.163 ABSTRACT Epithelial malignant tumors account for around 90% of all ovarian malignancies and are the deadliest gynecological malignancies and mucinous borderline ovarian tumors are the most common cases in Asia. According to World Health Organization (WHO) 2020, mucinous ovarian tumors are divided into mucinous cystadenoma, borderline mucinous tumor and mucinous carcinoma. Histopathological features of benign, borderline and invasive mucinous carcinoma can be found together in one tumor. The coexistence of these varied morphological features makes it difficult to establish a diagnosis due to the limited section evaluated and the large size of tumor. It can contribute to inaccurate diagnosis due to heterogeneity of the morphological features. Metastatic mucinous tumors which often resemble primary mucinous tumors in the ovaries. 1. Introduction Epithelial malignant tumors account for around 90% of all ovarian malignancies and are the most deadly gynecological malignancies. 1,2 According to statistical data from WHO (World Health Organization), there were 14.1 million cases of malignancy throughout the world in 2012 and ovarian malignancies ranked 18th of all malignancies most common by organ and the 7th most common malignancy in women worldwide. 3 Ovarian epithelial malignancies contribute to 150,000 deaths each year worldwide. 4 Based on data from the Indonesian Cancer Registry in 2011, malignant ovarian tumors rank 5th among all the most common malignancies by organ and 3rd most common malignancies in women in Jakarta. 5 Archive data from the Department of Anatomic Pathology, Faculty of Medicine, University of Indonesia/Cipto Mangunkusumo Hospital (2004 - 2013), mucinous epithelial tumors were the most common type (719 people) followed by serous ovarian epithelial tumors (457 people) and endometrioid types. 5 According to the World Health Organization (WHO) 2020, mucinous ovarian tumors are divided into benign, borderline and malignant mucinous tumors. This classification is carried out based on growth patterns, nuclear atypia and the presence or absence of invasion of the stroma and confluent growth. Borderline mucinous ovarian tumors are the most common cases in Asia (70% of borderline/atypical proliferative tumors) and the second most common in North America and Europe (30-50% of borderline/atypical proliferative tumors). 6 The histopathological features of benign tumors, borderline tumors and invasive mucinous carcinoma can be found together in one tumor. 6,7 The coexistence of these varied morphological features makes it challenging to establish a diagnosis due to the limited sections evaluated and the large size of the tumor. This can contribute to inaccurate diagnosis due to the possibility of missed foci of microinvasion carcinoma. 8 The difficulty of making a diagnosis, especially borderline mucinous ovarian tumors, is due to the heterogeneity of the morphological features such as microinvasion, intra- epithelial carcinoma, and mural nodules. For this reason, selection and sampling play an essential role in the accuracy of the diagnosis made. This literature review aims to provide information and study histopathological aspects