YAP1 and neoplasm: The pathological diagnostic criteria of HEHE proposed by the WHO include (9): (1) Typical histological structure: epithelioid or dendritic tumor cells infiltrating hepatic sinusoids; (2) Characteristic cytological findings: cytoplasmic vacuolization (primitive vascular lumen) containing red blood cells; (3) Immunophenotype: at least 2 vascular endothelial markers positive (CD31/CD34/FVIIIRAg); (4) WWTR1-CAMTA1 or YAP1-TFE3 fusion gene was detected by molecular pathology.