Fibrous dysplasia in combination with aneurysmal bone cyst of the occipital bone and the clivus: case report and review of the literature

OBJECTIVE AND IMPORTANCE: Fibrous dysplasia of the cranium is a relatively uncommon disorder that affects primarily the anterior cranial region; its occurrence in the cranial base in combination with aneurysmal bone cyst (ABC) constitutes an extremely rare condition, only two cases of which have been reported previously in the literature. It is important to recognize and treat these cases properly because of the special location in the cranial base and the possibility of neural structure impingement. CLINICAL PRESENTATION: We report the case of a 19-year-old man with a slowly enlarging mass of the occiput, with computed tomographic and magnetic resonance imaging revealing involvement of petrous and basisphenoid bone and growing ABC. INTERVENTION: Open biopsy confirmed the diagnosis of fibrous dysplasia. Partial excision of the lesion and removal of the ABC were performed in a second stage after embolization. CONCLUSION: ABC associated with fibrous dysplasia of the cranial base may enlarge rapidly after puberty and require excision. This is facilitated by preoperative embolization.