I believe non-vascular comes from sketchy but amboss says these tumors are "benign hepatocytes arranged in nodules separated by fibrous septa that contain aberrant blood vessels."
FA 2024 also doesnt mention that they are non-vascular
There are some Uworld questions related if someone can check if they specifically mention this tumor being non-vascular or just that they rarely have rupture/hemorrhage
Source: AMBOSS - https://next.amboss.com/us/article/pS0L0f?utm_source=navbar&utm_medium=anki&utm_campaign=anki&utm_term=focal%2Bnodular%2Bhyperplasia&guid=C.ka%2523Po%252Aeh&aid=44e7ea3f-36db-4448-a954-96b909d6a296&uid=ZJMgZspDa#Zf305479b55d8250579deab87ac1ac103
not needed