腹腔鏡下に切除した肝機能異常を呈した肝副葉の1例

A case of liver dysfunction in the accessory lobe of the liver which was resected by laparoscopic procedure

◆要旨：患者は38歳，男性．血液所見でalkaline phosphatase（以下，ALP）の高値を指摘され当院を受診した．ALPは2,116IU/lと高値であり，腹部CTにて左上腹部に肝左葉と連続する腫瘤を認めた．肝外突出型の血管腫を疑い，破裂の危険性も考慮して腹腔鏡下手術を行った．腹腔鏡所見では腫瘤と肝S2は間膜で連続し，間膜内部に数本の太い脈管を認めた．自動縫合器を用いて腫瘤を切除した．病理検査にて腫瘤に腫瘍成分はなくほぼ正常の肝小葉構造を認め，肝副葉と診断した．肝副葉はきわめて稀な肝の形態異常で，有茎性で大きなものは捻転を起こす危険性があり，手術適応である．肝周辺に腫瘤を認めた際には本疾患も念頭におく必要がある．また，その手術には腹腔鏡が非常に有用であった．

A 38-year-old man was referred to our hospital because of elevation of serum alkaline phosphatase（ALP） level. Abdominal computed tomography（CT） demonstrated a large mass lesion with probable connection to the left lobe of the liver at the left subphrenic area. Extrahepatic hemangioma was suspected and laparoscopic procedure was performed. Laparoscopic observation demonstrated the tumor, connected to the liver by a mesenterium containing some vessels, the tumor was resected using an automatic suture device. Histological examination revealed that the tumor consisted of almost normal hepatic tissue and thus we diagnosed it as an accessory lobe of the liver（ALL）. His postoperative course was uneventful. ALL is an extremely rare hepatic malformation. Resection is recommended if the ALL is pedunculated, because torsion of ALL can be the cause of acute abdominal pain. If there is an unknown tumor around the liver, ALL should be suspected. For this condition, laparoscopic procedure is very useful.