A female patient in her 40s with abdominal pain was referred to our hospital for esophagogastric varices and splenomegaly due to extrahepatic portal vein obstruction (EHPVO). The hematologist at the referring hospital determined a JAK2V617F mutation, indicating the involvement of myeloproliferative neoplasm (MPN).

Esophagogastroduodenoscopy revealed esophagogastric varices (LmF2CbRC2, Lg-cfF3RC1, and Lg-bF3RC0). Superior mesenteric computed tomography (CT) angiography revealed portal vein obstruction with cavernous transformation; however, the images indicated that the esophagogastric varices were not supplied through the left gastric vein. Splenic CT angiography revealed esophagogastric varices supplied by splenic blood flow, which confirmed the primary involvement of the splenic venous system in esophagogastric varices.

The patient required prophylactic treatment for variceal bleeding before anti-thrombotic therapy for EHPVO with MPN. We performed a laparoscopic modified Hassab's operation followed by endoscopic variceal ligation and anti-thrombotic therapy, considering her portal hemodynamics. Postoperatively, marked leukocytosis and thrombocytosis caused by MPN were treated with cytoreduction therapy for hydroxyurea. She was healthy with esophagogastric variceal eradication two years postoperatively.

The majority of patients with EHPVO are referred to gastroenterologists; however, underlying coagulopathy may be present and require hematological management. Laparoscopic modified Hassab's operation should be considered for cases of refractory esophagogastric varices that are not associated with the left gastric vein.