The Almost-Normal Liver Biopsy: Presentation, Clinical Associations, and Outcome.

Liver biopsies obtained for abnormal liver enzymes or unexplained ascites occasionally appear histologically almost normal. The differential diagnosis for these cases is challenging because literature addressing this topic is lacking. We aimed to establish a differential diagnosis and determine clinical associations and outcomes for almost-normal liver biopsies. Ninety-seven histologically almost-normal liver biopsies were collected from 2 institutions. All cases lacked significant inflammation, fatty change, biliary tract disease, vascular disease, nodular regenerative hyperplasia, iron overload, inherited metabolic or storage disorder, viral hepatitis, or fibrosis. Biopsies for follow-up of known liver diseases were excluded. Transplant biopsies, lesion-directed biopsies, biopsies obtained during bariatric surgery, liver donor biopsies, and biopsies to evaluate methotrexate toxicity were excluded. Clinical (including follow-up) and laboratory data were collected. The frequency of almost-normal liver biopsies was 0.6% and 3.7% at the 2 institutions. The most common biopsy indications were elevated liver biochemistries or clinical findings that suggested portal hypertension. In 70 patients (72%), an associated clinical abnormality was identified; the most common were autoimmune systemic inflammatory conditions (18%), vascular/ischemic events (13%), metabolic syndrome (11%), drug effects (8%), and inflammatory conditions of the gastrointestinal tract (7%). The median follow-up period was 4.3 years (range=0 to 10 y); detailed clinical follow-up was available for 66 patients (68%). Liver biochemistries normalized in 32 patients (48.5%) and remained elevated in 34 (51.5%). Seven patients (7.2%) eventually developed chronic liver disease (autoimmune hepatitis [n=3], primary biliary cirrhosis [n=3], cryptogenic cirrhosis [n=1]). This multicenter study determines the differential diagnosis for almost-normal liver biopsies; this will guide pathologists in subsequent workup efforts in these challenging cases.