Utility of P57 Immunohistochemistry in Differentiating Complete Mole from Partial Mole

Background: Molar pregnancy is basically a gestational trophoblastic neoplasia that is a complication of pregnancy. Depending on the balance of chromosome in the egg, molar pregnancy is divided into two main subtypes; complete and partial. Objectives: To find out the utility of p57 IHC in differentiating complete more from partial mole. Methods: This was a cross sectional study. The study was conducted in the Department of Gynecological Oncology, Dhaka Medical College Hospital, Dhaka, Bamgladesh. At July, 2019 to June, 2020. All patients who were diagnosed as molar pregnancy were selected by purposive sampling. Thereafter, they were scrutinized according to eligibility criteria and 50 patients were finalized. A pre-tested, observation based, peerreviewed data collection sheet was prepared before study. An informed written consent was taken after explanation regarding the study procedure. Molar tissue was obtained by suction and evacuation of uterus from all the cases. Then the sample was sent for HPR & IHC. Immunohistochemistry evaluation of all cases was performed from molar tissue & also from endometrium. Data regarding clinical, biochemical and surgical profile were recorded. Data were compiled, edited, analyzed. Data analysis were expressed in frequency, mean, standard deviation, percentages and ratio. Results: Among 50 patients, the highest 27(54%) belonged to 26-35 years, which was subsequently followed by 21(42%) patients belonged to 19-25 year’s age group. Rest 2(4%) were from 36-40 year’s group. The mean age of the patients was 27.36±2.79 (age range: 19-40) years. The highest 35(70%) were in 2nd gravida. Besides 8(16%) and 6(12%) were in their 1st and 33rd gravida. Rest 11(2%) was on her 4th gravida. Out of 50 patients, the highest 23(46%) patients presented at 12-16 week of gestational age, 13(26%) and 10(20%) patients presented at <12 weeks and 17-20 weeks of gestational age respectively. Only 4(8%) patients present of 21-24 weeks of gestational age. Out of 50 patients, 39(78%) were complete mole and rest 11(22%) were diagnosis as partial mole on the basis of HPR diagnosis. Out of 39 CM diagnosis by HPR, 79.84% were correct diagnosis determined by p57 immunohistochemistry. On the contrary, among 11 confirmed PM diagnosis by HPR only 27.27% were reconfirmed as correct diagnosis by p57 immuhohistochemistry. Extra villous trophoblast in p57 IHC expressed highest percentages in both CM and PM (84% vs 100%). Likewise, cytotrophoblast shows the highest in PM (100%) though it had the lowest expression in CM (6%). Vilous stromal cells had 82% expression in PM whereas 10% expression in CM, Decidua expression was 60% and 78% in CM and PM respectively. Conclusion: The effectiveness of p57 IHC test may reliably identify CM and may be used in association with the histological findings to distinguish CM from its mimics.