Figure FIG. 5.

Histological changes in the “normalization” of fibrous dysplastic lesions. von Kossa and Giemsa (A and B) and H&E (C and D) staining of lesional tissue from patient 7 (18 yr old) with high mutation levels (A and C) and from patient 10 (sample b, 35 yr old) with low mutation levels (B and D). In patient 7, bone is poorly mineralized, and there is excessive osteoid (* in A). Osteoblasts display a distinctive retracted, stellate morphology (white arrows in A, black arrows in C), characteristics that are typically found in FD lesions. In patient 10, mineralization is normal (B), and normal‐appearing cuboidal osteoblasts cover the bone‐forming surfaces (white arrows in B, black arrows in D).