Polyostotic fibrous dysplasia (FD) is a rare pathology characterized by the abnormal and gradual replacement of normal bone (calcium hydroxylapatite of osteoid matrix) with fibrous connective tissue. Aneurysmal bone cyst (ABC) is a tumor-like benign lesion with blood-filled cavities that can affect virtually any bone in the body. We report on a 20-year-old male presenting with an extremely rare pathology of FD with ABC formation of the skull, fourth rib and humerus. Our case report represents a novel literary addition to rare FD with ABC pathologies. Optimal diagnosis of this rare pathology can be achieved by a full body evaluation for clinical and radiographic FD with or without ABC, and optimal treatment for this rare pathology is the maximum surgical excision of the tumor and/or soft tissue.