These growths are from a fungus called cedar quince rust or another type of rust. The disease requires two hosts and its symptoms include yellow/orange spots on the leaves (there are a few on your plant).

I'd recommend pruning off these enlarged areas of growth. The rust spores infect the leaves in Springtime. Rust is typically a cosmetic issue but occasionally weakens shrubs. If you decide to use a fungicide, it usually requires 1 - 2 application in April/May. If using chemicals, follow the instructions on the label and do not apply during bloom.

So, I can do this with a retractable exacto knife, as the pruner shears seem to be to clumsy?

Thanks, Mr. Kluck

If you are able to make a clean cut with the exacto knife, that's ok. You need to be careful to avoid making unnecessary cuts to the main branches.