Background: It may be difficult to differentiate the consecutive occurrence of two independent molar pregnancies from gestational trophoblastic neoplasia after the initial molar pregnancy, especially when the interval between them is short.
Case: A 25-year-woman who had had a complete hydatidiform mole 6 months earlier presented with a 6-week history of secondary amenorrhea. Serum human chorionic gonadotropin had increased to 19,857 micro-international units/mL, with no gestational sac demonstrated. Dilation and curettage was performed. Pathologic examination identified a tiny amount of hydropic villi compatible with complete hydatidiform mole. Analysis of short tandem repeat polymorphisms revealed that the molar tissues of the first and second complete hydatidiform moles were of different genetic origin. The patient went into remission spontaneously without chemotherapy.
Conclusion: Genetic profiling was useful to discriminate a recurrent mole from suspected gestational trophoblastic neoplasia.