Imaging spots liver disease that biopsies can't confirm—new study reveals why
Researchers found that nearly 4% of patients diagnosed with metabolic liver disease by imaging show no fat buildup in biopsies, creating diagnostic confusion. Those with advanced fibrosis face real health risks, but the majority remain stable—findings that could reshape screening protocols and reduce unnecessary interventions.
Originaltitel: Characteristics and outcomes of patients with imaging-defined MASLD and histological steatosis grade S0.
Väsentlig diagnostisk övervägande för leverpatologi: Nya data visar att cirka 4 procent av patienter med bilddiagnostisk MASLD-diagnos saknar steatosgradning S0 vid leverbiopsi — ett fenomen som kliniker måste bedöma noggrant för att undvika missklassificering. Studien analyserade 3 273 biopsier från 16 centra och identifierade 123 fall med denna diskrepans. Drygt 29 procent av dessa patienter uppvisade avancerad fibros ("utbränd" MASLD) med påvisad risk för leverrelaterade händelser, medan övriga saknade sådan progression. I uppföljningsbiopsier visade 93 procent fortsatt frånvaro av eller mild steatosis. Orsaksanalys avslöjade tre mekanismer: utbränd sjukdom, ojämn fettfördelning i levern (påvisad via MRI-PDFF) samt variation mellan patologer och inom biopsisektioner. Institutioner i Kina, Sydkorea, Hong Kong och Italien deltog. För inköpschefer och regulatörer är slutsatsen tydlig: ensidig tillit på biopsigradning är otillräcklig. Multimoda imaging och standardiserad patologbedömning måste integrera diagnostiska protokoll.
BACKGROUND AND AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent chronic liver disease, and liver biopsy remains the gold standard for diagnosis. However, a subset of patients diagnosed with MASLD by imaging paradoxically exhibit steatosis grade S0 upon liver biopsy, posing a diagnostic challenge. This study investigates the outcomes and causes of "steatosis 0". METHODS: "Steatosis 0" was defined as imaging-detected MASLD with a biopsy-defined steatosis grade S0. We used global cohorts to evaluate outcomes, histologic progression via paired biopsies, and possible causes. The cause analysis included MRI-PDFF for fat distribution, pathologist consistency testing, and comparison of serial biopsy sections. RESULTS: In a follow-up cohort of 3,273 biopsy individuals from 16 centers, 123 (3.8%) exhibited "steatosis 0". Of these, 29.3% of them had advanced fibrosis ("burnt-out" MASLD) and demonstrated a risk of liver-related events, while those without advanced fibrosis had no such events. In the paired-biopsy cohort of 1,865 patients, 74 (4.0%) individuals initially showed steatosis grade S0; among them, 93.2% retained no or mild steatosis on follow-up biopsy. MRI-PDFF assessments in 42 MASLD patients revealed heterogeneous hepatic fat distribution, with some segments showing steatosis grade S0 despite elevated average liver fat. Inter-pathologist variability and discrepancies across consecutive biopsy sections contributed to misclassification of steatosis grade. CONCLUSION: "Steatosis 0" represents a potential diagnostic gray zone in MASLD. It may be caused by "burnt-out" MASLD, uneven liver fat distribution, or variability in pathological assessment. Understanding the causes and implications of "steatosis 0" is critical for diagnosis and management.