I'm peeling potatoes and there's a few that have these quarter-sized "tumor" looking like things (see photo). You can't peel them off. I cut them out, each one of the "tumors" are pretty deep. Its slightly black, moldy and the potato is discolored wherever the "tumor" is. Does anyone know what happen to this potato? Is the rest of the potato still edible after you cut out the "tumors"