Regional portal hypertension is a relatively rare cause of upper gastrointestinal bleeding and is often missed due to lack of understanding by clinicians, so it is necessary to raise awareness of this disease. Anatomically, the pancreas is at the hub of the portal circulation, and pancreatic disorders can directly affect the splenic vein, superior mesenteric vein, and portal vein; the relationship between the pancreas and splenic vein is particularly close. Isolated splenic vein obstruction generally refers to isolated splenic vein thrombosis, but also includes some rare obstruction due to compression or stretching of the splenic vein. Gastrointestinal bleeding due to isolated splenic vein embolism is receiving increasing attention. Sutton reviewed 53 cases of splenic vein embolism in combination with pancreatic disease from 1900 to 1968, including pancreatic tumors (19 cases), pancreatitis (6 cases), trauma (4 cases), and pancreatic cysts (3 cases), of which 29 cases were associated with gastrointestinal bleeding. 45% had gastrointestinal bleeding, 56% were pancreatitis and 9% were pancreatic tumors. 65% of Madsen’s 209 cases were caused by pancreatitis and 18% were associated with pancreatic tumors. Regional portal hypertension in the gastrosplenic region usually presents with four main features: (1) pancreatic disorders; (2) fundus or both lower esophageal varices; (3) splenomegaly; and (4) normal liver function. However, some patients have only some or none of these manifestations. The most common site of gastrointestinal bleeding in isolated splenic vein obstruction due to pancreatic disease is rupture of the submucosal varices in the fundus of the stomach. Tumors in the caudal part of the pancreatic body are prone to infiltration, compression or occlusion of the splenic vein due to thrombosis; tumors in the head of the pancreas are also possible, but often until late in the course of the disease, and in a few patients regional portal hypertension and upper gastrointestinal bleeding may occur due to inadequate establishment of collateral circulation on the omentum. Imaging methods are important for the diagnosis of this disease. Ultrasound and CT can detect splenic vein thrombosis and also confirm some concomitant pathological conditions. Isolated splenic vein occlusion with collateral circulation often has characteristic CT manifestations; tethered angiography venous phase is the gold standard for diagnosis. Bok analyzed 76 patients with islet cell tumor and found 10 cases with splenic vein invasion, and the mode of invasion was: (1) vein obstruction; (2) vein compression; and (3) tumor growth into the vein. Splenic vein invasion usually occurs in “non-functional” islet cell tumors, which may not have obvious systemic symptoms and have a longer growth time and larger size (>6 cm in diameter). In contrast, islet cell tumors present with systemic symptoms at an early stage and therefore do not show splenic vein invasion. The combination of islet cell tumor with splenic vein invasion or obstruction does not indicate advanced disease or difficulty in surgical resection. The treatment of regional portal hypertension in the gastrosplenic region combined with upper gastrointestinal bleeding is mainly splenectomy. If the site of bleeding is confirmed during angiography in patients with stable circulation, it can be treated with transcatheter embolization so that the procedure can be performed on an elective or semi-emergency basis, otherwise emergency surgery is required. For regional portal hypertension caused by islet cell carcinoma of the pancreas, surgical cure is possible if early diagnosis is made.