<s>[INST] context: Cirrhosis of the liver would lead to inability of the portal system to accommodate blood flow. Blood backs up toward systemic circulation, draining to the inferior vena cava, with pooling at areas of portal-caval anastomoses. The left gastric vein (portal) meets the esophageal vein (caval) and enlarges or expands in instances of cirrhosis. The left colic and middle colic veins are both simply tributaries to the portal system, excluding this as the correct answer. The inferior phrenic and superior phrenic veins are both systemic veins and would not be affected by portal hypertension. The same can be said for the renal and lumbar veins, both components of the caval-systemic venous system. The sigmoidal and superior rectal veins are both components of the portal venous system and would not engorge due to the portal-caval bottleneck experienced in cirrhosis. (The anastomoses between the superior rectal veins and middle or inferior rectal veins can expand in portal hypertension as hemorrhoids.) [/INST] question: A 67-year-old man has severe cirrhosis of the liver. He most likely has enlarged anastomoses between which of the following pairs of veins? | options: A: Inferior phrenic and superior phrenic B: Left colic and middle colic C: Left gastric and esophageal D: Lumbar and renal | answer: C </s>