Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 64 02 2026 04 03 11404 11404 Sepideh Aarabi assistant professor of emergency medicine 2024 12 06 2025 10 21 This case report describes a 67-year-old male who presented with right flank pain and unintentional weight loss, subsequently diagnosed with spontaneous portal vein thrombosis (PVT). Despite the absence of cirrhosis, malignancy, or identifiable prothrombotic conditions, imaging and anticoagulation therapy played a critical role in managing his condition. This report underscores the importance of early diagnosis, individualized anticoagulation therapy, and thorough investigation of underlying causes in the management of PVT. https://acta.tums.ac.ir/index.php/acta/article/view/11404 https://acta.tums.ac.ir/index.php/acta/article/download/11404/6022