Shared Features of Obliterative Portal Venopathy, Normal Liver, and Chronic Liver Disease: A Histologic and Morphometric Analysis.

Obliterative portal venopathy (OPV) is a cause of noncirrhotic portal hypertension and the diagnosis is challenging as the features are heterogenerous, subtle, and may be mistaken as "normal". We sought to compare OPV cases (n=72; 326 total portal tracts [PT]) with two control groups: control group 1 normal liver (n=40; 192 PTs) and control group 2 comprised of liver biopsies with chronic liver disease with OPV features (n = 40; 200 PTs). Morphometry was applied to determine the overall PT area & the luminal area of dystrophic portal veins (PVs). The frequency of absent native PVs was determined. Using trichrome-stained slides, approximately 5 PTs were randomly selected for morphometry utilizing the Philips IntelliSite Pathology Solution 3.3. Clinical data were extracted from electronic health records. Of the 326 PTs in the OPV cases, phlebosclerosis was found in 31.6%, densely fibrotic PTs in 12.7%, dystrophic PVs in 31.4%, and absent native PVs in 44.5%. When comparing the OPV group with control group 1, dystrophic PVs, absent native PVs, phlebosclerosis, fibrotic PTs, greater luminal area of dystrophic PV and higher ratio of dystrophic PV area to PT area were more frequently found in the OPV group. No significant difference in overall PT area was found. When comparing control group 2 with OPV cases, densely fibrotic PTs were more frequent as compared to OPV cases. This study shows that absent native PVs are the most frequent feature in OPV. Other features that are less frequent but still significantly different from normal liver include dystrophic PVs, greater luminal area of dystrophic PVs, phlebosclerosis, and PT fibrosis. Except for densely fibrotic PTs in control group 2, all other features showed similar frequency as OPV. Pathologists should be aware that OPV features may be present in liver biopsies from both normal and chronic liver disease.