Intrinsic Causes of Nonfibrotic Portal Hypertension—A Clinicopathologic Review of 56 Patients

Aim: The differential diagnosis of intrinsic nonfibrotic conditions that may lead to portal hypertension include hepatoportal sclerosis (HPS), nodular regenerative hyperplasia (NRH), and sinusoidal obstruction syndrome (SOS). In this article, we characterize the clinical features and outcome of these lesions when they manifest as portal hypertension. Methods: Data was collected through retrospective patient medical records. Results: Patients (HPS: 28, NRH: 17, SOS: 11) were identified more frequently in recent years. All groups presented with signs and symptoms of portal hypertension. All patients had complex medical histories. An elevated serum alkaline phosphatase occurred in all groups and an elevated bilirubin with SOS. Imaging of the liver with HPS and NRH suggested cirrhosis, which was not seen with SOS. 11%, 12%, and 9% of patients in the HPS, NRH, and SOS respectively, underwent transjugular intrahepatic portosystemic shunt placement to manage the complications of portal hypertension, while 43%, 24%, and 36% of patients respectively, received a liver transplant. Conclusions: Patients with HPS, NRH, and SOS had complex medical histories, likely contributing to the development of these lesions. They are recognized more frequently now. In contrast to HPS and NRH, SOS occurred in liver transplant recipients, was associated with elevated serum bilirubin, and imaging did not suggest the presence of advanced fibrosis/cirrhosis. Liver transplantation appeared to be a viable treatment for complications related to HPS and NRH. Retransplantation for SOS yielded mixed results. HPS, SOS, and NRH should be considered when evaluating liver specimens from patients with unexplained nonfibrotic portal hypertension. Key message: Intrinsic nonfibrotic causes of portal hypertension appear to be increasing in frequency. The differential diagnosis includes NRH, HPS, and SOS. These conditions are associated with complex diseases and possibly due to treatments. Pathologists need to be aware of this differential diagnosis when presented with liver biopsies performed to assess portal hypertension.