Porto-sinusoidal vascular disorder-type lesions in patients with early fibrotic stages of metabolic dysfunction-associated steatotic liver disease.

Background

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Objective

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a rising cause of chronic liver disease. Liver stiffness measurement (LSM) to assess disease stage is gaining popularity but can demonstrate heterogeneous results in clinical practice. Moreover, portal hypertension may develop early in MASLD in the absence of cirrhosis. These observations may be partially explained by features not assessed in the current NASH-CRN liver biopsy staging, including features of porto-sinusoidal vascular disorder (PSVD).

Methods

We conducted a retrospective cohort study in patients with MASLD who underwent biopsy between 2015 and 2022. All biopsies with NASH-CRN F0-F2 were screened for eligibility and revised in consensus by two expert liver pathologists. Primary objective was to assess the presence and severity of PSVD-type lesions. Secondary objectives included the grading of perisinusoidal fibrosis and to correlate histological features with LSM.

Results

We included 136 patients [60% male, median age 50y] with a median BMI of 30 kg/m2, 15% having F1 fibrosis and 85% F2 fibrosis. Median LSM (available in 54%) was 8.2 kPa. Portal venule stenosis affecting ≥50% of portal tracts was present in 26% of biopsies, and muscularisation of portal venules was present in 21% of biopsies. Perisinusoidal fibrosis was present in 97% of biopsies, respectively mild, moderate, and severe in 62%, 32%, and 3%. PSVD-type lesions did not correlate with LSM, but LSM did correlate with the degree of perisinusoidal fibrosis.

Conclusion

Portal venule stenosis (≥50%) and muscularisation of portal venules, both major criteria associated with PSVD, were found in 26% and 21% biopsies, respectively. Furthermore, the extent of perisinusoidal fibrosis correlates with liver stiffness and could explain the heterogeneity of LSM in MASLD.