Obliterative portal venopathy: A neglected and probably misdiagnosed disease with peculiar etiology in South America.

Background and Aim: Obliterative portal venopathy (OPV) is one of the causes of non-cirrhotic portal hypertension. However, many aspects of OPV remain unclear, including the etiology, pathogenesis, and natural history. The aim of this study was to describe the clinical features of OPV in a series of patients in Brazil in whom OPV was diagnosed through liver biopsy. Methods: Forty-three consecutive adult patients with OPV were retrospectively selected as a case series based on histologic criteria, defined by the presence of at least portal fibrosis, phlebosclerosis, disappearance and/or reduction of the caliber of portal vein branches, and exclusion of cirrhosis. Clinical and laboratory data were analyzed. Clinically significant portal hypertension was considered in the presence of esophageal varices and/or ascites. Results: The mean age of patients at diagnosis was 44.5 ± 11 years, who were predominantly female (81%). Clinically significant portal hypertension was found in 28% of cases. The most frequent indication for liver biopsy was the elevation of liver enzymes, mostly γ-glutamyl transferase (GGT) in 76% of patients, averaging 222 IU/L (upper limit of normality up to 40 IU/L) and alanine aminotransferase (ALT) in 64%, mean 84 IU/L (38 IU/L). One-third of our patients had exposure to medications, especially herbal medicines, at the time of enzymatic changes. Other risk factors highlighted were features of autoimmunity in 25% of patients or thrombophilia in 20%. Conclusion: OPV can be diagnosed even before the onset of portal hypertension, ALT elevation, and especially GGT elevation in most cases. Its etiology is not defined, but autoimmune diseases, thrombophilia, and the use of medications or herbal medicines may play a role.