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Pseudolesion in the right parafissural liver parenchyma on CT: The base is found in embryology and collagen content

Willemijn M Klein, Lianne J P Sonnemans, Sabine Franckenberg, Barbara Fliss, Dominic Gascho, Mathias Prokop, Wouter H Lamers, Jill P J M Hikspoors, Michael J Thali & Patricia Flach

abstract

BACKGROUND
Computed tomography (CT) images of livers may show a hypo-attenuated structure alongside the falciform ligament, which can be a focal fatty pseudolesion and can mimic a malignancy. The preferred location is on the right parafissural site, ventral in segment IVa/b. The etiology is not clear, nor is it known how the histology of this location develops. These are evaluated in this study.

METHODS
40 adult cadavers with autopsy and / or postmortem CT in a university hospital and a forensic center were included. Liver biopsies were taken at the left side of the falciform ligament as control, and at the right side as the possible precursor of a pseudolesion; these were examined for collagen and fat content. Cadavers with steatotic (>5% fat) or fibrotic (>2% collagen) control samples were excluded.

RESULTS
Significantly more collagen was present in the right parafissural liver parenchyma: median 0.68% (IQR: 0.32-1.17%), compared to the left side 0.48% (IQR: 0.21-0.75%) (p 0.008), with equal fat content and CT attenuation values. The etiophysiology goes back to the demise of the umbilical venes in the early embryonic and neonatal period.

CONCLUSIONS
The right parafissural area contains more collagen and an equal amount of fat compared to the control left side. This supports the hypothesis of delayed, 'third' inflow: the postnatal change in blood supply from umbilical to portal leaves the downstream parafissural area hypoperfused leading to hypoxia which in turn results in collagen accumulation and the persistence of paraumbilical veins of Sappey.
   
citation Klein W M, Sonnemans L J P, Franckenberg S, Fliss B, Gascho D, Prokop M, Lamers W H, Hikspoors J P J M, Thali M J, Flach P. Pseudolesion in the right parafissural liver parenchyma on CT: The base is found in embryology and collagen content. PLoS One 2020; 15:e0221544.
   
type journal paper/review (English)
date of publishing 27-01-2020
journal title PLoS One (15/1)
ISSN electronic 1932-6203
pages e0221544
PubMed 31986149
DOI 10.1371/journal.pone.0221544