McCune-Albright syndrome: radiological and MR findings.

McCune-Albright syndrome (MAS) is a non-inherited disorder due to the GNAS1 gene mutation. The syndrome is characterized with the triad of polyostotic fibrous dysplasia, pigmented skin lesions, endocrinopathy, and precocious puberty. We report the case of a 14-year-old boy, presenting with sclerotic type of polyostotic fibrous dysplasia. Radiological methods including plain X-ray film, MR and whole body bone scintigraphy suggested the diagnosis of MAS. MRI provided more directly perceived images and it was more sensitive in demonstrating the lesion: its shape, contents, especially the size of the affected region. Histopathological study and the identification of mutant gene finally confirmed the diagnostic result.