A 68-year-old female presents to hepatology for further management of chronic portal vein thrombosis (PVT). She was diagnosed with mesenteric vein thrombosis in 1995 after she developed acute onset of severe abdominal pain. She required exploratory laparotomy at which time the diagnosis was made and was treated with warfarin for six months. She underwent hypercoagulable workup which was negative. In 2003, she was noted to have extension of the superior mesenteric vein (SMV) thrombus into the portal vein. She was restarted on warfarin which she remains on. She has a history of esophageal and fundal varices on propranolol 600 mg daily. The varices were never treated endoscopically and she denies history of gastrointestinal bleeding. She has not had prior liver biopsy. Family history is negative for venous thromboembolism. Social history is negative for alcohol use. She has two healthy children and no history of miscarriage. Review of systems is negative for jaundice, icterus, pruritus, encephalopathy, ascites, or peripheral edema. On exam, abdomen is distended but soft and nontender. Splenomegaly is present and there is no obvious ascites. There are no chronic liver disease stigmata. Labs are significant for a platelet count of 80, normal liver function tests, normal albumin, and elevated INR in the setting of warfarin. MRI of liver with elastography reveals cavernous transformation of the intra- and extrahepatic portal veins with a prominent system of pericholecystic collaterals. Massive splenomegaly of 25 cm length is noted and the SMV is patent. There are no suspicious liver lesions. Stage III to IV liver fibrosis is noted. Transjugular liver biopsy shows extramedullary hematopoiesis without evidence of cirrhosis. Upper endoscopy with endoscopic ultrasound reveals grade III esophageal varices and type 1 gastroesophageal varices without stigmata of recent bleeding. No further intervention is recommended by surgery or interventional radiology and her beta blockade and anticoagulation are continued. Patient is referred to hematology due to liver biopsy finding of extramedullary hematopoiesis. Bone marrow biopsy reveals hypocellular bone marrow with marked myelofibrosis and molecular analysis is positive for JAK2 V617F mutation, consistent with a diagnosis of primary myelofibrosis. This case illustrates the importance of keeping in mind myeloproliferative neoplasms as a potential etiology of PVT, noncirrhotic portal hypertension, and massive splenomegaly.