Inflammation of the portal vein (large vein that carries blood from the stomach and intestines to the liver) or any of its branches: In medical school, Susan learned that pylephletitis can occur as a threatening complication of an hidden intra-abdominal or pelvic infection, like appendicitis or pancreatitis.

Pylephletitis combines pyle-, "a reference to the entry of the portal vein into the liver" + phlebos, "vein".