GNAS and fibrous dysplasia: The characteristic recurrent mutations in CTNNB1 (p.T41A, p. S45F) detected in desmoid‐type fibromatosis from five patients was not detected in plasma, nor were the recurrent GNAS (p.R201H, p.R201C) mutations detected in four and six patients with fibrous dysplasia and intramuscular myxoma, respectively, whose tumors harbored the relevant GNAS mutations.