Giant mucocele of the frontal sinus is a rare pathology of benign entity caused by retention of mucous secretions in the sinus. It may expand and erode the surrounding structures such as bones and cerebral parenchyma. The authors describe a patient with frontal giant mucocele involving the orbit, the ethmoid, and intracranial portion of the dura. The main presenting symptoms were diplopia and proptosis. A computed tomography scan and magnetic resonance imaging were performed to permit differential diagnosis from other pathologies such as ossifying fibroma, fibrous dysplasia, and other neoplasms. A single stage maxillofacial and neurosurgical approach to treatment was taken consisting in the removal of the mucocele and reconstruction of the eroded bones with cranial bone grafts. The dura was repaired with temporalis muscle fascia sealed with fibrin glue. Two years after surgery, the patient shows no recurrence and satisfactory morphologic and functional results.