Acute Appendicitis Complicated by Superior Mesenteric Vein Thrombosis: A Rare Case of Pylephlebitis in a Healthy Young Male.

Pylephlebitis is a rare but potentially life-threatening complication of various intra-abdominal infections, characterized by septic thrombophlebitis of the portal venous system. It is most commonly associated with conditions such as appendicitis, diverticulitis, cholecystitis, and other sources of abdominal sepsis. When the thrombosis extends to the superior mesenteric vein, it can result in bowel ischemia, infarction, and even death if not promptly diagnosed and treated. We present the case of a 29-year-old man with no prior comorbidities who developed acute appendicitis complicated by thrombosis of the superior mesenteric and ileocolic veins. He underwent a successful laparoscopic appendectomy and was treated with anticoagulation therapy. The patient showed steady clinical improvement and was discharged on oral anticoagulation after a 12-day hospital stay, with complete recovery observed at follow-up visits conducted one week and two weeks after discharge. This case underscores the importance of early recognition of pylephlebitis in intra-abdominal infections and demonstrates that prompt surgical and anticoagulation management can lead to favorable outcomes.