仲村 将光, 長谷川 潤一, 真井 博史, 松岡 隆, 市塚 清健, 関沢 明彦, 岡井 崇

Masamitsu NAKAMURA, Junichi HASEGAWA, Hiroshi SANAI, Ryu MATSUOKA, Kiyotake ICHIZUKA, Akihiko SEKIZAWA, Takashi OKAI

昭和大学医学部産婦人科学教室

Department of Obstetrics and Gynecology, Showa University School of Medicine

キーワード : placental chorioangioma, polyhydramnios, fetal anemia, sinusoidal pattern, Doppler ultrasound

本報告は胎盤血管腫の表在血管が胎内において破綻し，胎児貧血を来たした症例の世界で初めての報告である．症例は29歳，0回経妊．他院で妊婦健診を施行していた．妊娠28週の妊婦健診で，羊水過多と胎盤腫瘤を指摘され，精査のため当院紹介となった．初診時の超音波検査で，羊水ポケット87 mmと羊水過多を認めた．胎盤表面にはカラードプラ法で血流が豊富に描出される65×80 mmの有茎性腫瘤を認めたため，胎盤血管腫の診断で入院管理とした．入院時は児の形態学的評価を含め，羊水過多以外に異常を認めなかったが，徐々に血管腫は増大した．妊娠31週6日，超音波検査で児の中大脳動脈血流収縮期最大速度の上昇を認め，また胎児心拍数波形にsinusoidal patternを認めたことから，胎児貧血による胎児機能不全と診断し，緊急帝王切開を施行した．分娩時，羊水は血性であり，胎盤娩出時に血管腫表面の一部破綻がみられた．児にはヘモグロビン8.3 g/dl，アルブミン1.5 mg/dlと，貧血と低アルブミン血症を認め，血小板が19.1×10⁴/μlと正常であったことから，胎児貧血の原因は血管腫の破綻と考えられた．胎盤血管腫の症例に胎児貧血を認めた場合には，血管腫の破綻も鑑別診断すべきと考えられた．

To our knowledge, this is the first report of a case of fetal anemia due to rupture of a vein on the surface of placental chorioangioma. A 29-year-old primigravida was referred to us for clinical follow-up and serial ultrasonographic (US) surveillance. The patient had a normal course until a placental mass was noted by obstetric US examination at 28 weeks. Routine obstetric US images demonstrated a 65×80-mm hypoechoic, circumscribed, and ovoid intraplacental mass that protruded into the amniotic cavity. Amniotic fluid pocket was measured as 87 mm, and power Doppler images demonstrated remarkable flow within the anechoic spaces in the placental mass. The diagnosis of chorioangioma and polyhydramnios were made, and the patient was admitted to our hospital. At admission, we did not find any apparent complications such as fetal anomaly, anemia, growth restriction, or placental abruption. Following examinations, the size of the mass gradually increased, and the middle cerebral artery-peak systolic velocity (MCA-PSV) MoMs were also increased. Furthermore, the sinusoidal pattern appeared on the fetal heart rate tracing. Then, emergency cesarean section was performed under the diagnosis of non-reassuring fetal status due to fetal anemia. At the operation, we found that amniotic fluid was bloody due to rupture of the placental mass. Neonatal hemoglobin and albumin were 8.3 g/dl and 1.5 mg/dl, respectively, and the platelet count was within the normal range (19.1×10⁴/μl). The cause of fetal anemia was thought to be hemorrhage due to rupture of the placental mass. It has been suggested that we should pay attention to rupture of tumor vessels when we manage cases with chorioangioma complicated by polyhydramnios.