Pancreatic Cancer Presenting With Hematemesis and Hemorrhagic Shock Following Anticoagulation With Unfractionated Heparin for Cancer-Related Venous Thromboembolism.

Cancer-related venous thromboembolism (VTE) is a significant concern owing to its frequent occurrence and status as a leading cause of death in patients with cancer. Cancer-related VTE carries a higher risk of hemorrhage than VTE in patients without carcinoma. A 74-year-old woman with pancreatic head cancer presented with complaints of loss of appetite and weight loss. Contrast-enhanced computed tomography (CT) was performed for stage classification of pancreatic cancer, which incidentally revealed pulmonary thromboembolism. The patient remained clinically asymptomatic, with no evidence of hypoxemia or echocardiographic findings suggestive of pulmonary hypertension. Due to the unavailability of low-molecular-weight heparin for the treatment of acute pulmonary embolism and concerns about potential hemorrhage according to CT findings, unfractionated heparin was selected for its ability to be closely monitored and promptly discontinued if necessary. However, the treatment was immediately halted as the patient developed hematemesis and hemorrhagic shock. Subsequent CT confirmed gastrointestinal hemorrhage, and three-dimensional CT angiography identified the pancreaticoduodenal arcade as the source of bleeding. Emergency catheter angiography and transcatheter arterial embolization were performed, successfully achieving hemostasis. This case highlights the high risk of both recurrent VTE and bleeding complications in patients with cancer-related VTE, underscoring the need for individualized treatment strategies.