Clinically significant portal hypertension (PH) is defined as an elevation of the portal pressure gradient above 10–12 mmHg. While cirrhosis remains its most common cause, several non-cirrhotic forms exist, particularly in thrombotic conditions. Among these, myeloproliferative neoplasms (MPNs) represent a rare but important etiology of non-cirrhotic PH because of their chronic prothrombotic state.

The aim of this study was to describe the clinical and endoscopic features of PH associated with MPNs and to evaluate the impact of hematologic treatment on the evolution of complications.

This retrospective descriptive study spanned a four-year period. Included were adult patients with confirmed PH whose etiology was an MPN diagnosed either through the presence of JAK2, CALR, or MPL mutations, or through consistent bone marrow biopsy (BMB) findings. Clinical presentation, laboratory results, imaging, endoscopic features, and treatment outcomes were collected and analyzed.

Of the 220 patients diagnosed with PH, 9 individuals (4.1%) had an underlying myeloproliferative disorder. The mean age was 62.2 years (range 40–84), and males predominated (66%, male-to-female ratio 3:1).

The most common presenting symptom was upper gastrointestinal bleeding (44.4%), followed by anemia-related symptoms (33.3%) and abdominal pain (22.2%). Splenomegaly was universal among patients (100%), and two-thirds presented with massive splenomegaly extending to the umbilicus or left iliac fossa. Ascites, however, was present in less than half the cases (44.4%), suggesting that PH associated with MPNs may manifest differently from cirrhosis-related PH.

Ultrasound with Doppler revealed predominantly pre-hepatic causes of PH, with portal vein thrombosis (PVT) present in 77.7% of patients. Intra-hepatic forms accounted for 22.2% of cases. Notably, none of the patients exhibited Budd–Chiari syndrome, despite its known association with MPN-related thrombosis.

Genetic testing identified the JAK2 V617F mutation in 88.8% of patients, in line with its recognized prothrombotic potential. Bone marrow biopsy allowed the diagnosis of primary myelofibrosis in 66.6% of patients and essential thrombocythemia in 33.3% of cases. No cases of polycythemia vera or chronic myeloid leukemia were detected.

Endoscopic examination revealed high-grade esophageal varices in a majority of patients: grade III varices with red signs in 55.5%, grade II varices in 11.1%, and grade I varices with red signs in 22.2%. One patient had no esophageal varices but presented with hypertensive gastropathy. Gastric varices were found in 33.3% of patients, and ectopic varices—duodenal and rectal—were observed in 22.2%. Eight patients underwent endoscopic variceal ligation, with an average of 2.6 sessions (range 1–5), resulting in good clinical improvement.

Treatment combined management of PH (beta-blockers, endoscopic ligation, diuretics) with targeted therapy for the underlying MPN (hydroxyurea or ruxolitinib) and anticoagulation for thrombosis. Cytoreductive therapy produced an overall favorable response, with a reduction in spleen size in 50% of patients. Nonetheless, PH remained partially persistent, and no patient achieved re-canalization of the portal vein.

Complications during follow-up included two episodes of recurrent gastrointestinal bleeding (22.2%), a recurrence of ascites in one patient (11.1%), and one death (11.1%).

Portal hypertension associated with myeloproliferative neoplasms displays a distinctive clinical profile. Presentation often includes inaugural gastrointestinal bleeding and marked splenomegaly, whereas ascites is less common. Endoscopic findings tend to be severe, with a high prevalence of advanced esophageal varices and frequent involvement of gastric or ectopic varices.

Although hematologic therapy does not reverse portal thrombosis, it provides significant stabilization of PH manifestations and contributes to the reduction of splenic enlargement in a substantial proportion of patients.