坂江 遥¹, 玉井 努¹, 宇都 浩文¹, 室町 香織¹, 大西 容雅¹, 門野 潤³, 東 美智代⁴, 井本 浩³, 梛野 正人², 井戸 章雄¹

Haruka SAKAE¹, Tsutomu TAMAI¹, Hirofumi UTO¹, Kaori MUROMACHI¹, Hiroka ONISHI¹, Jun KADONO³, Michiyo HIGASHI⁴, Yutaka IMOTO³, Masato NAGINO², Akio IDO¹

¹鹿児島大学大学院医歯学総合研究科 消化器疾患・生活習慣病学, ²名古屋大学大学院腫瘍外科, ³鹿児島大学大学院医歯学総合研究科 心臓血管・消化器外科学, ⁴鹿児島大学大学院医歯学総合研究科 腫瘍学講座病理学

¹Department of Digestive and Life-style Disease, Kagoshima University Graduate School of Medical and Dental Sciences, ²Division of Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, ³Cardiovascular and Gastroenterological Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, ⁴Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences

キーワード : primary hepatic neuroendocrine tumor (PHNET), contrast-enhanced ultrasonography (CEUS)

症例は40歳，女性．皮膚の紅斑を主訴に皮膚科を受診し，鑑別として皮膚筋炎が考えられ，悪性疾患の精査目的に施行した腹部造影CT検査にて，肝S4/8に動脈相で辺縁部から濃染し，平衡相で軽度wash outされる径32 mmの腫瘤を認めた．腹部超音波検査Bモードでは，腫瘤のほとんどは境界明瞭な高エコーを呈し，内部の一部に嚢胞状の低エコー域を認めた．腹部造影超音波検査では，腫瘍は14秒後から染影されはじめ，38秒後に全体が均一に濃染された．門脈相では均一で肝実質とほぼ等エコーであった．嚢胞状の部位は染影しなかった．後血管相のadvanced dynamic flowで明瞭なdefectを呈した．肝腫瘍生検の病理診断では，肝原発神経内分泌腫瘍（primary hepatic neuroendocrine tumor: PHNET）が考えられたため，経皮経肝的門脈塞栓術を施行後に肝右葉3区域と尾状葉切除術を施行した．肝腫瘍は免疫組織学的に，chromogranin Aとsynaptophysinが陽性で，MIB-I indexは1.4％であった．肝外に原発巣を認めなかったことから，肝原発神経内分泌腫瘍 Grade 1と診断した．PHNETは稀な疾患であり，造影超音波検査で評価した報告例は少なく，文献的考察を踏まえて報告する．

A 40-year-old woman presenting with erythema was admitted to dermatology, where a mass 30 mm in diameter was detected on abdominal computed tomography (CT) at segment 4/8 of the liver. Abdominal ultrasonography (US) showed a hyperechoic mass with cystic change. Contrast-enhanced US revealed homogeneous hyperenhancement in the arterial phase, but consisting of a non-enhanced area with a cystic lesion, and hypoechoic in the post-vascular phase around normal liver parenchyma, with a defect was seen in the Kupffer phase. These findings were not specific for any tumor, so we performed a percutaneous tumor biopsy, and diagnosed primary hepatic neuroendocrine tumor (PHNET). We performed percutaneous transportal embolization before hepatectomy (right trisectionectomy and caudate lobectomy). Immunohistochemically, the tumor cells were positive for the neuroendocrine markers (chromogranin A, synaptophysin) and the Ki-67 index was 1.4%. No primary lesion was found, leading to a classification of primary hepatic neuroendocrine tumor (PHNET) grade 1 and over. PHNET is rare and has a poor prognosis. We report a case of PHNET with a review of the literature.