A primary or metastatic liver tumor sometimes blocks portal venous flow and causes a focal sparing in the fatty liver. We herein report a case of segmental sparing due to the portal tumor thrombus extending from the metastatic liver tumor. The present case demonstrates characteristic computer-associated tomographic findings, a distal oval hypodense tumor with proximal "crescent-shaped sparing", which may indicate underlying portal tumor thrombus at the apex of the sparing.