Expand/Grow Shader Mask, Possible?

Hello, I am trying to figure out a way to expand a mask with the shader nodes, not scale, but grow the edges of the mask. For example, imagine a 10px line in the form of a circle and you wanted to keep the circle in it’s same position and same radius, but expand that line thickness to 50px. Scaling won’t work.

Thank you Blender friends.