IntroductionPylephlebitis is defined as septic thrombophlebitis of the portal venous system, usually secondary to infection or inflammation in the abdomen. In the current report, we present a case of pylephlebitis that complicated the course of a very common pathology, diverticulitis.Case presentationA 62-year-old Caucasian woman with a history of sigmoid diverticulitis presented to our facility with a three-week history of abdominal pain, fevers, chills, loss of appetite and fatigue. Her laboratory test results showed leukocytosis and elevated alkaline phosphatase. A computed tomography scan revealed portal vein thrombosis and a sigmoid diverticulitis with an abscess. Our patient was given pipercillin-tozabactam followed by sigmoid colectomy and loop transverse colostomy. A peritoneal fluid sample culture grew Escherichia coli. Our patient had an uneventful post-operative course and the leukocytosis resolved in the next four days. She improved clinically and was discharged home on ertapenem and enoxaparin. A follow-up computed tomography scan two weeks later showed a new pelvic abscess that was drained by a pigtail catheter but there was no change in the portal venous thrombus. A repeat computed tomography scan one month later revealed resolution of the pelvic abscess but persistence of portal vein thrombus, for which enoxaparin was continued.ConclusionsThis is a classic case of pylephlebitis that demonstrates the importance of recognizing that the portal vein thrombus is infected and treating the condition appropriately.