RESULTS: Immunohistochemical (IHC) staining for CD34, vWF and ASMA was performed in clinically and histologically well-characterised NRH (n = 15) and OPV (n = 47) liver specimens. Among the 47 OPV cases, 37 (78.7%) had concurrent features of NRH. CD34 positive staining was mainly confined to small vessels in the portal tracts and LSECs in periportal areas, a finding similar to that in non-NRH/OPV livers. However, expression of vWF in LSECs was positive in the compressed sinusoids of NRH and in a patchy or geographic pattern, particularly prominent in the perivenular areas and dilated sinusoids of OPV cases. HSCs were negative for ASMA in all NRH and OPV cases.
CONCLUSIONS: Our findings indicate that NRH may be a subtle but common concurrent morphological feature in OPV. The aberrant expression of vWF in LSECs suggests that endothelial injury may play a role in the pathogenesis, which may thus aid in the recognition and diagnosis of NRH and OPV, particularly when confronted with otherwise apparent normal liver histology on needle biopsy.