A giant intracranial mucocele associated with an orbitoethmoidal osteoma

The authors present a rare case of a giant intracranial mucocele associated with an orbitoethmoidal osteoma in a patient suffering from a generalized convulsive disorder. The broad pedicle of the osteoma had penetrated the cribriform plate and extended intracranially to form a nodular mass in the olfactory groove. The intracranial portion of the osteoma was surrounded by a mucocele. Both the cyst wall and multilayered intracystic septations of the mucocele were indented by layers of the osteoma. Although the extracranial portion adhered to the mucosa of the ethmoidal sinus, there were no signs of sinus obstruction. No direct communication other than the osteoma was identified between the mucocele and the ethmoidal mucosa. The large cerebral defect, which the mucocele occupied, communicated directly with the lateral ventricle without any intervening membranous structures. A frontal craniotomy is recommended for exposure of the lesion and plastic repair of the dural defect.