Histopathological and immunohistochemical features of early hydatidiform mole in relation to subsequent development of persistent gestational trophoblastic disease.

OBJECTIVE: To examine histomorphological and immunohistochemical findings in hydatidiform moles to determine whether any features can reliably predict clinical behavior. STUDY DESIGN: Blinded semiquantitative review of histological and immunohistochemical findings in cases of partial hydatidiform mole (PHM) (N = 50) and complete hydatidiform mole (CHM) which either spontaneously resolved (N = 50) or required chemotherapy (N = 50). Immunostains assessed included MLH1, MSH2, nm23, TERT, p53, EGFR, and CerbB2 based on previous data. RESULTS: There were marked morphological differences in various criteria between CHMs and PHMs, including the proportion of villi with abnormal trophoblast hyperplasia (29% vs. 6%, respectively). However, there were no significant differences in any morphological parameters between CHMs that spontaneously resolved and those that subsequently required chemotherapy. Similarly, there were no clinically useful differences regarding any immunostaining scores between CHM groups. CONCLUSION: Neither morphological nor immunohistochemical features can reliably predict subsequent requirement of chemotherapy in CHMs.