A patient with adult extrahepatic portal obstruction, of which distinction from intrahepatic cholangiocarcinoma was difficult.

A 51-year-old Japanese male with chief complaints of slightly high fever and epigastralgia was hospitalized at our facility. The inflammatory response was enhanced, and liver dysfunction was observed. Abdominal ultrasonography demonstrated a hyperechoic lesion occupying the left portal vein, and abdominal plain CT indicated a low density of the lesion with a clear boundary, measuring about 3 cm x 2 cm, between the porta hepatis and segment IV of the liver. Contrast CT showed no enhancement in the arterial and portal phases, but a reduction in the density inside the tumor in the equilibration phase was noted. MRI showed hypointensity by T1-weighted imaging and hyperintensity by T2-weighted imaging. Angiography demonstrated an obstruction of the left portal vein and superior mesenteric vein, and endoscopic retrograde cholangiography revealed a constriction in the left intrahepatic bile duct. Since the possibility of intrahepatic cholangiocarcinoma could not be excluded, extended left hepatectomy combined with caudate lobectomy was performed. The tumor, measuring 31 mm x 21 mm x 20 mm, was pathohistologically diagnosed as an extrahepatic portal obstruction. Extrahepatic portal obstruction is an important disease that is sometimes difficult to rule out oncologic origin.