Harnessing p57 Immunohistochemistry to Enhance Diagnostic Accuracy in Molar Pregnancies: An Insight

Introduction Molar pregnancy (hydatidiform mole) is a premalignant form of gestational trophoblastic disease, occurring in approximately one in 1,000 pregnancies. It is characterized by abnormal swelling of chorionic villi and excessive trophoblastic proliferation. Accurate differentiation between complete hydatidiform moles (CHMs) and partial hydatidiform moles (PHMs) is crucial, as CHMs carry a higher risk of progressing to persistent trophoblastic disease or choriocarcinoma. p57 immunohistochemistry (IHC), regulated by the maternally expressed CDKN1C gene, is a key diagnostic tool due to its distinct expression patterns in different molar subtypes. Methods A prospective observational study was conducted over 18 months at Dr. B.R. Ambedkar Medical College & Hospital, in Bangalore, India, involving 25 cases: 15 clinically diagnosed molar pregnancies and 10 products of conception used as controls. Detailed clinical histories were recorded, followed by histopathological examination and p57 IHC analysis. All cases underwent statistical evaluation. Results Among the 25 cases, 12 (48%) were diagnosed as CHM, three (12%) as PHM, and 10 as non-molar controls. CHM cases showed negative p57 staining in villous cytotrophoblasts, whereas PHM cases exhibited weak to moderate nuclear positivity. Control cases demonstrated strong nuclear positivity. The use of p57 IHC showed a statistically significant correlation (p < 0.001) with accurate differentiation between complete and partial moles. Conclusions This study confirms that p57 IHC is a reliable and effective diagnostic tool for distinguishing between CHM and PHM. Its clear differential staining pattern enhances diagnostic precision, informs clinical decision-making, and minimizes the risk of misdiagnosis, supporting its routine implementation in the evaluation of molar pregnancies.