PROLIFERATIVE ACTIVITY IN PLACENTAS WITH HYDROPIC CHANGE AND HYDATIDIFORM MOLE AS DETECTED BY KI-67 AND PROLIFERATING CELL NUCLEAR ANTIGEN IMMUNOSTAINING

Complete hydatidiform moles (CHM) and partial hydatidiform moles (PHM) represent different clinicopathologic entities. To obtain prognostic and therapeutic information about both entities, it is important that pathologic classification be as accurate as possible. The distinction of molar pregnancy and an abortus with hydropic changes (AHC) can some times be very difficult. The acquisition of 2 antibodies against nucle ar antigens expressed in cycling cells Ki-67 and proliferating cell nu clear antigen (PCNA), allow the study of trophoblastic proliferation i n CHM, PHM, and AHC. The purpose of this study is to determine whether immunocytochemical stains can help in the distinction between those e ntities. All materials were obtained by curettage from 95 patients wit h hydropic villi evident on microscopic examination. The 95 cases incl uded 33 cases of CHM, 42 cases of PHM, and 20 cases of AHC. In the cas e of the Ki-67 staining, the mean was much lower in the AHC group (8.7 %) than in the PHM group (65.3%) or in the CHM group (84.6%). In the c ase of PCNA staining, the mean differences among the 3 groups (AHC, 23 .1%; PHM, 80%; and CHM, 89.2%) were all statistically significant. On the basis of the means and the Gaussian results, it appears that the K i-67 distribution gives a better separation among the 3 groups. In con clusion, proliferative activity is an additional useful parameter for evaluation of molar pregnancies and hydropic changes, with Ki-67 stain ing allowing better separation than PCNA staining does.