青木 信裕¹, 岩崎 信広², 今井 幸弘³, 岡部 純弘⁴, 千葉 勉¹

Nobuhiro AOKI¹, Nobuhiro IWASAKI², Yukihiro IMAI³, Yoshihiro OKABE⁴, Tsutomu CHIBA¹

¹京都大学大学院医学研究科消化器内科学, ²神戸市立医療センター中央市民病院臨床検査技術部腹部超音波室, ³神戸市立医療センター中央市民病院病理科, ⁴大阪赤十字病院消化器科

¹Department of Gastroenterology and Hepatology,Kyoto University Graduate School of Medicine, ²Division of Abdominal Ultrasound,Kobe City Medical Center General Hospital, ³Department of Clinical Pathology,Kobe City Medical Center General Hospital, ⁴Department of Gastroenterology,Osaka Red Cross Hospital

キーワード : Budd-Chiari syndrome, focal nodular hyperplasia, liver transplantation, Sonazoid, ultrasonography

症例は20歳，女性．5年前に本態性血小板血症で内服治療歴がある．腹部膨満感と黄疸を主訴に2006年2月精査を施行し，肝生検にてうっ血性肝障害を認めるも，その原因は不明であった．2006年7月には腹部造影CTで肝静脈の完全閉塞が認められ，カラードプラ法で門脈右枝の逆流と傍臍静脈の再開通が観察されたことから，肝静脈閉塞型Budd-Chiari症候群（BCS）と診断された．以後の経過観察中の超音波検査で肝に2cm以下の辺縁低エコー帯を有し，内部不均一な充実性腫瘤が多数観察されるようになった．Sonazoid®を用いた造影超音波検査が行われたが，早期相で腫瘤中心部まで動脈が流入し，その後車軸状に広がる血管構築像が描出された．後期相では，周囲肝実質より腫瘤の方が高エコーに染影された．末期肝硬変であったため，患者・家族の希望もあり2007年3月生体肝移植が施行された．切除肝の病理組織学的検索では，肝実質は肝静脈閉塞に起因するうっ血性肝硬変の像であり，腫瘤は中心瘢痕と流入血管を有するfocal nodular hyperplasia（FNH）様過形成結節であった．カラードプラ法による肝の血行動態評価および造影超音波検査による肝腫瘤の血行動態評価が，BCSおよびこれに伴った腫瘤性病変の診断にきわめて有用であった．

The patient was a 20-year-old woman who had undergone medical treatment for essential thrombocythemia for 5 years. She had complained of abdominal distension and jaundice of uncertain etiology when she was thoroughly examined in February 2006. As late as July 2006, the needle biopsy specimen showed congestive liver damage; the abdominal enhanced CT scan, complete hepatic venous obstruction; and the pulsed Doppler ultrasonogram, reverse flow in the right branch of the portal vein with recanalization of the paraumbilical vein. Accordingly, our diagnosis was hepatic venous thrombosis-type Budd-Chiari syndrome (BCS). Follow-up ultrasonography revealed multiple nodules up to 2 cm in diameter in the enlarged liver and showed a heterogeneous solid echoic pattern with a halo. Contrast-enhanced ultrasonography with Sonazoid® was carried out. The imaged nodules demonstrated a spoke-wheel pattern after blood had flowed directly to the center of the liver in the early phase. In the late phase, the stained nodules were more echogenic than the background liver tissue. Liver transplantation was carried out at the request of the patient and her family in March 2007 because of progression of liver failure. Pathologically, the liver explant showed congestive cirrhosis resulting from hepatic venous obstruction. Most of the nodules contained central satellite scar and radial dilated vessels, consistent with the histologic indication of focal nodular hyperplasia (FNH). Ultrasonography using a contrast agent appears to be the method of choice for evaluating dynamic state of liver circulation in BCS and proved invaluable in diagnosing the nodules associated with it in this case.