Acute Portal Vein Thrombosis Associated With Anastrozole Therapy: A Report of a Rare Case.

Portal vein thrombosis (PVT) is a rare but potentially life-threatening condition that most often occurs in the setting of liver disease, malignancy, local inflammation, certain medications, or hypercoagulable disorders. We report a rare case of acute PVT in a 71-year-old woman with a history of breast cancer in remission who was receiving adjuvant anastrozole therapy and presented with abdominal pain. CT revealed extensive thrombosis involving the portal vein and superior mesenteric vein. The workup excluded malignancy recurrence and infection, revealing only heterozygous factor V Leiden. With no other clear cause identified, anastrozole was considered the most likely etiology. This case highlights the importance of recognizing aromatase inhibitors as potential contributors to venous thrombosis.