Monostotic fibrous dysplasia (ossifying fibroma) of the mastoid.
D000293:Adolescent; D003937:Diagnosis, Differential; D005350:Fibroma / Q000175:diagnosis / Q000473:pathology; D005357:Fibrous Dysplasia of Bone / Q000175:diagnosis; D006801:Humans; D008297:Male; D008416:Mastoid; D010002:Osteitis Fibrosa Cystica / Q000175:diagnosis* / Q000473:pathology; D010016:Osteoma / Q000175:diagnosis* / Q000473:pathology