Histopathological and Immunohistochemical Expression of Ovarian Tumours: A Crosssectional Study from a Tertiary Care Centre Indore, India

Introduction: Ovarian tumours constitute 3% of all malignancies in women and 30% of all cancers affecting the Female Genital Tract (FGT). Cervical and endometrial cancers have a higher incidence than ovarian cancer. According to GLOBOCAN 2022 (Global Cancer Observatory’s estimates for the year 2022), there were 722,138 ovarian cancer cases worldwide, including 45,333 new cases reported in India. India has the second highest incidence of ovarian cancer globally (6.6%), with the highest rates noted in Pune and Delhi. Immunohistochemical (IHC) markers play a crucial role in subtyping, grading, and assisting in the diagnosis and prognosis of ovarian tumours. Aim: The present study aimed to analyse the histopathological and immunohistochemical expression of ovarian tumours and evaluate the role of IHC in differentiating primary ovarian neoplasms from metastatic tumours. Materials and Methods: The present ambispective two-year cross-sectional study was conducted from January 2023 to December 2024 on 188 cases at Sri Aurobindo Institute of Medical Sciences, Indore, Madhya Pradesh, India. Haematoxylin and Eosin (H&E)-stained sections along with IHC-stained slides of ovarian neoplasms were prepared and examined. IHC was performed in 58 cases using common primary markers such as Cytokeratin 7 (CK7), Cytokeratin 20 (CK20), Paired Box Gene 8 (PAX8), and Wilms’ Tumour Gene 1 (WT1) to identify primary ovarian tumours. Secondary markers such as Caudal-Type Homeobox 2 (CDX2), Special Adenine-Thymine-rich SequenceBinding Protein 2 (SATB2), Oestrogen/Progesterone Receptors (ER/PR), and Calretinin were used to differentiate tumours of FGT, Gastrointestinal Tract (GIT), breast, and metastatic origin. Additional markers like Inhibin and Octamer-Binding Transcription Factors (OCT) were used for morphological subtyping of sex cord-stromal and germ cell tumours. Results: Out of the 188 cases, surface epithelial tumours were the most common (149 cases), including 82 benign serous cystadenomas, 24 malignant Serous Carcinomas (SCs), and 22 mucinous cystadenomas. Most metastatic tumours (21 cases) presented with omental nodules and abdominal pain and were predominantly of SC type. IHC was performed on 58 cases using CK7/CK20 followed by WT1 and Napsin A, which helped differentiate ovarian tumours from other genitourinary tract tumours. Of these, 37 cases were confirmed as primary ovarian tumours. These included 24 cases of SC, 4 adult granulosa cell tumours, and one case each of Mucinous Carcinoma (MC), neuroendocrine carcinoma (small cell carcinoma), Sertoli-Leydig cell tumour, seromucinous cystadenoma, borderline serous tumour, and mature cystic teratoma. Conclusion: The most common neoplasms observed were surface epithelial tumours, with benign serous cystadenoma being the predominant type, most frequently affecting women of reproductive age. IHC played a significant role in tumour differentiation, grading, and prognostication.