Abstract

Introduction: Borderline ovarian mucinous tumors are the grey zone areas in histopathology. Differentiating borderline mucinous tumors from malignant cystadenocarcinoms is a diagnostic challenge to a histopathologist. Mitotic rate is a traditional and practical method to determine proliferative activity but it’s hampered by several factors. This study is designed to evaluate if Ki-67 labelling index is useful in determining the grade of primary mucinous ovarian neoplasms and its superiority over mitosis

Materials and Methods: A cross-sectional study was conducted in the department of pathology, in a tertiary health care centre over the period of 5 years. The study includes Cases of mucinous cystadenomas, borderline mucinous tumors and cystadenocarcinomas. Formalin fixed and paraffin embedded sections are reviewed, with representative sections being selected for IHC. Labeling index is determined with a light microscope.The number of mitosis is calculated in 10 high power fields (40X) in the most mitotically active area. Data was collected & entered in Microsoft office excel 2007 sheet. This was then analysed using software SPSS version 19.0.The statistical test used was Fischer’s exact test.

Results: The mean Ki-67 labeling index in benign, borderline and malignant tumors were 1.74 %, 26.45 %, 62.71 %respectively. A Ki-67 labeling index of 42% may be used to discriminate between borderline and malignant tumors. Mitotic rate between benign, borderline and malignant tumors was statistically significant (p value <0.001). However 2 borderline tumors did not show mitosis.

Conclusions: There is a superiority in using ki67 labelling index over mitosis for differentiating benign borderline and malignant tumors. Ki 67 can be used as an additional diagnostic tool to differentiate mucinous tumors

Keywords:  Ki 67 labelling index, Mitotic rate, Mucinous ovarian tumor.