Fibrous dysplasia is a benign bone lesion of unknown etiology. Bone involvement usually is solitary (monostotic). Multiple forms (polyostotic) associated with extra skeletal symptoms, particularly cutaneous pigmentation, endocrine dysfunction and precocious puberty is called McCune-Albright syndrome (MAS). We report the case of a 40-year-old man who presented with left mandibular body expansion and intermittent suppuration from the skin sinus tract formation since he was 18 years old. He had skeletal deformities, limping, and multiple skin pigmentation. X-ray revealed multiple fractures and radiolucent lesions in numerous bones. Laboratory analysis showed an increased serum alkaline phosphatase. Precocious puberty was determined upon taking the patient's history. The patient's height was 148 cm. Microscopic findings of the mandibular lesion, clinical presentation and X-ray findings were strongly diagnostic for MAS.