Hi Mandy and welcome to GoY - any chance of a photo?

Or more info - a single orange growth? Where? How big is it?

if the orange growth appears on dry dead wood it sounds like a fungi called Coral Spot, simply cut out dead growth, chances are your Willow tree is stressed out and coming to the end of its days especially if its a miniature Killmarnock type which are grafted onto another willow tree of a simular genus(prone to problems)
look out for sucker growth further down the main stem these growths starve the graft of esential moisture, remove whenever they appear The treatment to cure this tree is called SYSTANE fungicide pay around 6.99 or buy another tree pay around 12.99 ask before you buy if the tree is from a reliable virus free source. not B & Q there`ll look at you sideways, they are not use to people with knowledge