Liver histopathology in patients with hepatic masses and the Abernethy malformation

The Abernethy malformation (AM) is a congenital venous malformation in which the splanchnic venous return bypasses the liver and drains directly into the systemic circulation. This deprives the liver of hepatotrophic growth factors and allows metabolic products of digestion to enter the systemic veins without the benefit of passing through the liver. The histologic features of liver biopsies in children with an AM were reviewed.

A retrospective review of liver biopsies in patients with AM between 1997 and 2017 was performed. Patients were divided into two groups for comparison of histologic features: presence (M+) or absence (M-) of a coexistent liver mass on imaging. Biopsies were reviewed by a pediatric pathologist. Chi-square test was used for statistical analysis between groups. Significance was assigned to p values <0.05.

Eighteen liver biopsies were reviewed. Masses were present in only 6 patients who had a liver biopsy. Masses were observed with similar frequencies in either type of the Abernethy malformation (I or II). Nine of 12 M- patients and 3/6 M+ patients had the type I AM. Histologically, all patients were noted to have small or absent portal veins. Isolated capillaries were seen more frequently in patients with a known liver mass (p = 0.045), while crowding of portal tracts was more commonly seen in patients without a liver mass (p = 0.019).

Liver biopsies in patients with AM demonstrate abnormal vascular and parenchymal histologic features. Livers with coexistent masses were more commonly found to have features suggesting an increased dependence on arterial blood supply.

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