What ARE Gouty Tophi? May 19, 2012 | Gout Symptoms. To correctly explain tophi, it is important to clarify that “tophi” is plural; “tophus” is singular. Tophi are deposits of urate crystals underneath the skin that grow due to excessive levels of uric acid in the bloodstream. Typically, a tophus with grow larger and larger without intervention and will be accompanied by frequent and severe symptoms of gout.