腹腔鏡下手術による診断と治療により良好な妊娠経過を得た、卵巣出血との鑑別に難渋した子宮内外同時妊娠の一例

抄録

　Heterotopic pregnancy, defined as simultaneous intra- and extrauterine gestation is diagnostically challenging. The incidence rate of heterotopic pregnancy is 27-fold higher after assisted reproductive technology than after spontaneous conception; nevertheless, it is relatively rare (reported incidence rate 0.003％). We report a case of laparoscopically diagnosed heterotopic pregnancy. A 37-year-old primipara, who conceived after intrauterine insemination in conjunction with ovulation induction, was referred to our hospital for evaluation of abdominal pain at 6 weeks' gestation. Transvaginal ultrasonography revealed a viable intrauterine pregnancy and a left adnexal mass (3 cm) suggestive of hematoma or ectopic pregnancy. Laboratory test results showed total serum β-human chorionic gonadotrophin of 33,783 mIU/mL and serum hemoglobin (Hb) of 10.7 g/dL. Evaluation on the 2^nd day of hospitalization showed left adnexal mass enlargement to 5 cm with serum Hb level decreased to 8.5 g/dL. Magnetic resonance imaging (MRI) revealed a hematoma and a cystic area surrounding the left adnexa; however, the lesion was not definitively diagnosed. Transvaginal ultrasonography performed on the 9^th day of hospitalization revealed a gestational sac containing a yolk sac, surrounding the left adnexa, which led to a high index of clinical suspicion for heterotopic pregnancy. Laparoscopy revealed a distended left fallopian tube compatible with ectopic pregnancy; therefore, we performed left salpingectomy. Histopathological examination of the resected specimen showed villi within the left fallopian tube, which confirmed diagnosis of an ectopic pregnancy. The intrauterine pregnancy remained intact, and the patient delivered a healthy male neonate at term. MRI and ultrasonography may not definitively diagnose heterotopic pregnancy; however, laparoscopic surgery is a useful diagnostic and therapeutic approach for heterotopic pregnancy.