Impact of oral contraceptive pills on the number and epithelial type of ovarian cortical inclusion cysts; A clinicopathology and immunohistochemical study

Background: Ovarian epithelial cancers are among the most lethal women s cancers. There is no doubt about the preventive role of oral contraceptive pills (OCPs) in development of ovarian cancers. But, there are limited number of studies to address the effect of these agents on the number of cortical inclusion cysts (CICs), their epithelial type and suppression of the metaplastic phenomenon by these pills. The aim of this study was to clarify the role of these agents in the prevention of these cyst formation and tubal metaplasia and also examine the mesenchaymal-epithelial theory in this context by immunohistochemical methods. Methods: The representative section(s) of ovarian cortex from a total number of 184 consecutive total abdominal hysterectomy with bilateral or unilateral salpingo-oophorectomy specimens were examined for main number of CICs and their epithelial type between two groups of the patients. Group A included the patients who were on oral contraceptive pills for more than 5 years. All of the subjects with other contraceptive methods or a history of less than 5 years contraceptive pills usage were stratified in group B. Sections from 20 cases in which more than five inclusion cysts were found in, are selected for IHC staining with calretinine and PAX8 as markers for mesothelium and mullerian epithelium respectively. Results: The main age of the patients was 51.67 years with no significant differences between two groups. The main number of cysts were 1.27 and 3.23 in group A and B respectively (P=0.0001).Similarly the main number of CICs, lined by tubal epithelium, was significantly different between two groups (0.65 vs 2.65, P=0.0001). In IHC staining 123 out of 150 CICs (82%) were PAX+ while only 7 CICs (4.8%) showed positive reaction for calretinin irrespective of type of epithelium.Conclusion: We concluded that the use of OCP for more than five years in women can reduce significantly the number of ovarian CICs and number of the CICs with tubal type epithelium. In addition, our IHC findings confirmed the Mesenchaymal- Epithelial Transition –MET hypothesis about tubal change of CICs epithelium.

Keywords:

Oral Contraceptive Pills , Ovarian Cortical inclusion cyst , Ovarian Cancer