Hepatic angiomyolipoma originating in the caudate process : a case report

症例は41歳女性.検診の腹部超音波検査で尾状葉突起部に突出型,35mm大の肝腫瘤を指摘された.HBs抗原ならびにHCV抗体は陰性であった.経口避妊薬などの内服歴はなかった.腹部CT, MRI,超音波検査で腫瘤全体は早期で強く造影され,後期ではwash outされた.MRIではT1強調で低信号,T2強調で一部やや高信号であった.血管造影でも腫瘍は強く濃染された.PET-CTでは腫瘍に^{18}F-FDGの集積を認めなかった.AFPならびにPIVKA-IIは基準値内であった.肝細胞癌など悪性腫瘍の可能性も完全には否定出来ず,増大傾向を認めた為,診断かつ治療目的で,腹腔鏡補助下肝尾状葉突起部部分切除術を施行した.最終診断は肝血管筋脂肪腫(肝AML),筋腫型であった.術後の経過は良好で,第9病日に軽快退院した.肝AMLの中でも腫瘍内に脂肪成分が殆どない筋腫型の場合,他の疾患との鑑別は困難である.また腫瘍が小さい場合は細小肝癌との区別に苦慮する場合もある.そのため,診断治療目的に腹腔鏡(補助)下肝切除術を行うことは有用と思われる.本症例は腹腔鏡下手術が手技的に難しい尾状葉原発であったが,突起部からの突出型であったため,腹腔鏡補助下で手術を行い,確定診断が得られた.肝尾状葉原発腫瘍であっても,症例を選択すれば,腹腔鏡(補助)下肝部分切除術は可能である.

A 41-year-old woman was admitted to our hospital for an abdominal ultrasonography, which revealed a hypoechoic liver tumor. She had no past medical history and no risk factors for liver disease. Dynamic computed tomography and MRI revealed a protrusive increasing liver tumor about 4cm in maximal diameter arising from segment I. These examinations using contrast medium showed enhancement in the early phase and washout in the delay phase. The T1-weighted MR image showed a low intensity, and the T2-weighted image showed a little high intensity. Hepatic angiography showed a hypervascular tumor. Liver function tests were normal, and levels of serum tumor markers, including Alfa-fetoprotein and protein induced by vitamin K absence or antagonist II, were within normal ranges. Laparoscopic operation was indicated for the purpose of diagnosis and treatment. The extrahepatic growing soft tumor originating in the caudate process was confirmed, and laparoscopy-assisted partial hepatectomy was performed. The operation time was 299 minutes, and the blood loss was 270ml. Postoperative course was uneventful. Histology showed a myomatous angiomyolipoma of the liver. Laparoscopy-assisted liver resection is useful for a tumor with difficult diagnosis.

肝血管筋脂肪腫

尾状葉

腹腔鏡下肝切除術