CTNNB1 and fibrous dysplasia: Vimentin, SMA, and desmin were used for the present case, and only vimentin showed strong positivity with equivocal positivity for SMA.Other differential diagnoses, such as a desmoid tumor, show nuclear ß-catenin positivity and CTNNB1 or APC mutation, while fibrous dysplasia reveals GNAS gene mutation.