The characteristics of Laennec's capsule around the hepatic veins: A histological study based on 71 liver surgical specimens

Background: Laennec's capsule is a fibrous membrane attached to the surface of the liver, which is independent of the hepatic veins. However, the presence of Laennec's capsule surrounding the peripheral hepatic veins is controversial. This study aims to describe the characteristic of Laennec's capsule around the hepatic veins at all levels. Methods: Seventy-one hepatic surgical specimens were collected along the cross and longitudinal sections of the hepatic vein. Tissue sections of 3-4 mm were cut and stained with hematoxylin and eosin (H&E), resorcinol-fuchsin (R&F), and Victoria blue (V&B). Elastic fibers were observed around the hepatic veins. They were measured using K-Viewer software. Results: Morphologically, we observed a thin, dense fibrous layer (so-called Laennec's capsule) around the hepatic veins at all levels, which was different from the thick elastic fibers of the hepatic vein wall. Therefore, there was a potential gap between Laennec's capsule and the hepatic veins. Laennec's capsule was visualized significantly better with R&F and V&B staining compared to H&E staining. The thickness of Laennec's capsule around the main, first, and secondary branches of the hepatic vein were 79.86 +/- 24.20 mu m, 48.41 +/- 18.25 mu m, and 23.56 +/- 10.03 mu m in the R&F staining, and 80.15 +/- 21.85 mu m, 49.46 +/- 17.52 mu m, and 25.05 +/- 11.03 mu m in the V&B staining, respectively. They were significantly different from each other (P < .001). Conclusion: The hepatic veins were surrounded by Laennec's capsule at all levels, including the peripheral hepatic veins. However, it is thinner along the vein branches. The gap between the Laennec's capsule and hepatic veins shows potential supplemental value for liver surgery.