Androgenetic/biparental mosaic/chimeric gestation: A case report

Abstract

Introduction: Androgenetic/biparental mosaic/chimeric (ABMC) conceptions are a rare group of gestational trophoblastic disease (GTD) that arise as a result of mosaicism or chimerism and are characterized by hydropically enlarged and variably sized villi. Currently, there are very few reports describing ABMC conceptions; there are 13 total in the literature, and even more rare are those with a molar component. Case Report: A 27-year-old female patient at 6+4wga presented to the clinic with a complaint of new vaginal bleeding and was diagnosed with a pregnancy of unknown location. The patient re-presented to the clinic at 8+4wga by last menstrual period (LMP) for a follow-up ultrasound. A serum human chorionic gonadotropin (hCG) was ordered and returned at 424,008 mIU/mL. A transvaginal ultrasound demonstrated a heterogeneous “snowstorm” appearance throughout uterine cavity, with a concern for complete mole in the setting of a significantly elevated beta hCG. The patient underwent a suction dilation and curettage with ultrasound guidance. Pathology returned the following report: The specimen was sent to pathology and DNA ploidy returned as diploid; however, p57 demonstrated a discordant staining pattern characterized by expression in villous cytotrophoblast but the absence in villous stromal cells was characteristic of androgenetic/biparental mosaic/chimeric gestation. No fetal parts were identified in gross examination of the specimen. Conclusion: Androgenetic/biparental mosaic/chimeric (ABMC) conceptions are important to accurately diagnose because the molar form carries an increased risk for persistent gestational trophoblastic diseases. There are few case reports published regarding ABMC cases. We present this case to provide additional data to the field and emphasize the utility for p57 immunohistochemistry and genetic testing to be performed.