The histopathological diagnosis and differentiation between partial mole (PM) and complete mole (CM) bears difficulties. Hence, additional methods rather than morphology can be useful to reach the proper diagnosis. Immunohistochemical (IHC) analysis using antibodies such as p57 and Ki-67 can be used to solve this problem. This study was done to investigate the role of p57 and Ki-67 IHC in distinguishing between CM, PM, and hydropic abortion (HA).Patients and methods
Twenty cases of molar pregnancies – 10 (CM) and 10 (PM) – and 10 HA diagnosed on histopathological criteria were studied histopathologically along with IHC using antibodies against p57 and Ki-67. The cases were collected in a retrospective manner from Pathology Lab, Faculty of Medicine, Mansoura University from January 2015 to December 2015.Results
We found that CM demonstrated enlarged villi with circumferential trophoblastic hyperplasia. Villous stromal cells and cytotrophoblast were negative for p57. PM demonstrated hydropic, irregularly shaped villi with scalloped contours, trophoblastic inclusions, and mild circumferential trophoblastic hyperplasia. Villous stromal cells and cytotrophoblast were diffusely positive for p57. In all 10 CM cases, the Ki-67 proliferation index was relatively high (>26% of cells) with complete absence of p57 immunostaining in the cytotrophoblasts and villous stromal cells in comparison with PM cases with statistical significance (P<0.001).Conclusion
Our study further confirms the valuable role of p57 in the diagnosis of CM augmented by the traditional histopathological criteria. Ki-67 has a limited value in differentiating between some cases of PM and CM. The best possible use of Ki-67 is to differentiate between molar and nonmolar pregnancy along with other histological parameters, especially trophoblastic proliferation and villous enlargement.