村上 孟司¹, 日高 庸博¹, 城戸 咲¹, 福嶋 恒太郎¹, 永田 公二², 田口 智章², 加藤 聖子¹

Takeshi MURAKAMI¹, Nobuhiro HIDAKA¹, Saki KIDO¹, Kotaro FUKUSHIMA¹, Koji NAGATA², Tomoaki TAGUCHI², Kiyoko KATO¹

¹九州大学病院産婦人科, ²九州大学病院小児外科

¹Department of Obstetrics and Gynecology, Kyushu University Hospital, ²Department of Pediatric Surgery, Kyushu University Hospital

キーワード : congenital diaphragmatic hernia, pulmonary agenesis, tetralogy of Fallot, lung hypoplasia

先天性横隔膜ヘルニア胎児の肺低形成を超音波で評価するにあたって，肺胸郭断面積比（lung-to-thorax transverse ratio: LTR）や肺断面積児頭周囲長比（lung area to head circumference ratio: LHR）が用いられるが，これらの指標は健側肺がターゲットであり，患側肺は考慮しない．今回，胎児期に左横隔膜ヘルニアと診断，LTRやLHRは低値でなかったにもかかわらず，生後に重篤な経過をたどり，手術時に左肺の無形成が判明，救命できなかった症例を経験した．症例は33歳の初産婦，胎児胃像の胸腔内脱出を指摘され妊娠28週で当科紹介された．胎児超音波検査で左横隔膜ヘルニアと診断，同時にファロー四徴症の合併を指摘した．主肺動脈には順行性血流が観察された．胎児左胸腔に胃と肝左葉を認め，LTR 0.17，LHRのo/e比は51％，胃の位置Grade1（Kitano）であり，重症な肺低形成を示唆しなかった．妊娠36週に胎児機能不全の診断で緊急帝王切開術を施行した．児は2,056 gの男児で，Apgar score は1/7点であった．外表異常として左拇指欠損，両耳介欠損を認めた．2生日で手術が行われ，左肺は完全欠損の状態であった．術後は体外式膜型人工肺により生命維持を行ったが離脱できることなく，肺高血圧は進行し，15生日に死亡した．本児の予後が不良であった原因として心疾患の合併は重要な因子であったが，術後に膨らむべき肺が完全欠損していたことの影響も小さくないと考えられた．横隔膜ヘルニア胎児の画像評価では，健側肺のみならず患側肺にも注目することの意義を再認識した．

We present a patient with prenatally diagnosed congenital left diaphragmatic hernia, in whom complete agenesis of the left lung was found postnatally. The fetal sonographic examination was not suggestive of a poor prognosis (lung to thorax transverse area ratio, 0.17; observed/expected lung area to head circumference ratio, 51%). The stomach was in the left thoracic cavity and was classified as Kitano’s grading grade 1. An additional complication was present, as the patient had tetralogy of Fallot. A male infant, weighing 2,506 g, was born via cesarean section at 36 weeks’ gestation. His postnatal respiratory condition was unexpectedly poor, and left lung agenesis was diagnosed during surgery for his congenital diaphragmatic hernia. Severe respiratory insufficiency persisted after the surgery; the infant could not be withdrawn from extracorporeal membrane oxygenation, resulting in early neonatal death on postnatal day 15. The impact of the complicated congenital heart disease should not be ignored as a cause of death in this infant; however, the fact that the left lung was congenitally absent, and therefore could not expand even after the surgery, was considered a significant factor influencing the clinical course. Pulmonary agenesis is extremely rare. During the prenatal imaging assessment of a fetus with congenital left diaphragmatic hernia, both the right and left lung volumes should be carefully evaluated.