A case of an ectopic pregnancy that occurred in the uterine subserosa, which had to distinguish from trophoblastic disease

Abstract

An intraperitoneal pregnancy is an extremely rare condition, and its early diagnosis is difficult due to subtle early symptoms compared with those of ectopic pregnancies in other locations. We encountered a woman with an intraperitoneal pregnancy that occurred in the serosa of the posterior uterine wall. She was referred to our hospital for investigation of an increase in the urinary hCG level after a diagnosis of a miscarriage at another hospital. A 30-year-old para one woman had discharged pieces of deciduous membrane eigtht weeks and six days after the last menstrual period, and subsequently underwent evacuation of the uterus after a diagnosis of incomplete abortion was made. However, due to persisting genital bleeding and an increase of urinary hCG level (from 1092 mIU/ml to 3224 mIU/ml in nine days), she was referred to our hospital. On initial examination, ultrasound showed an approximately 2cm cystoid-like lesion in the uterine posterior wall. Color Doppler confirmed blood circulation in this site, and CT demonstrated enhancement along the tumor wall at the early stage of the arterial phase. MRI T2-weighted image confirmed a tumor of high-signal intensity, but a clear image of a gestational sac could not be observed. Because the initial examination did not detect genital bleeding and sign of the abdominal cavity hemorrhage, we opted for conservative chemotherapy (MTX 17.5 mg/body × 5 days) to treat a possible clinical invasive mole or a ectopic pregnancy, at 15 weeks and two days after the last menstrual period. However, the treatment strategy was altered because of severe adverse reactions such as stomatitis and digestive symptoms and an increase in serum hCG. As there was a slight increase in tumor size, open surgery was performed 16 weeks and six days after the last menstrual period. Although the morphological effect of chemotherapy made the judgment difficult, pathological examination of the surgical specimen showed the prominent presence of intermediate trophoblasts and the absence of marked invasion into the muscle layer. Based on these findings combined with the clinical course and changes in serum hCG levels, the diagnosis of an ectopic pregnancy was reached. The serum hCG levels dropped gradually after surgery and hysterosalpingography performed three months after surgery did not reveal any abnormalities in the passage through both tubes. [Adv Obstet Gynecol, 68 (2) : 112-117, 2016 (H28.5)]