Fibrous dysplasia is related to benign fibro-osseous lesions characterized by the progressive replacement of the original bone tissue by fibrous connective tissue. This condition may be present in a single bone, described as monostotic fibrous dysplasia, or in up to 75% of the whole body, described as polyostotic. Its etiology is unknown; however, studies report a relation between the enzymatic and metabolic modifications and genetic mutations. It is more common in the first 2 decades of life, with no prevalence of sex. It is clinically a painless tumefaction, promoting facial asymmetry. Radiographically, it presents as a "glass-matte" aspect opacification. The proposed treatment can be surgical or conservative, depending on the functional and aesthetic impairment. This study aims to report a case and to present the tomographic and anatomic aspects of monostotic fibrous bone dysplasia in a 14-year-old female patient.