Giant Arachnoid Cyst Associated with an Orbital Meningocele: A Case Report and Cystoperitoneal Shunt Management.

Background: Intracranial arachnoid cysts (ACs) are space-occupying lesions that typically remain stable in size and clinically silent over time.

Methods: We describe an unusual pediatric case of enlarged AC impressive by its compressive phenomena. An 11-month-old girl presented with remarkable macrocephaly associated with a cystic orbital tumor. CT scan and MRI studies revealed a large intracranial ACs extending in the orbit with an orbital meningocele (OM). The intracranial cyst did communicate with the orbital one into a bony defect in the right inner region of the orbital roof and represses the globe outward. A cystoperitoneal shunting procedure was performed to remove the mass effect as soon as possible and facilitate normal development.

Conclusions: Cysts in infants younger than 1 year of age are remarkably different from those in older children and adults in terms of cyst localization and enlargement. Classically described complications result from compression of adjacent structures and include focal neurologic involvement, headaches and seizures and developmental deficits, or macrocephaly in younger children. There are few cases of ACs with ophthalmic manifestations reported in the literature. The paucity of literature prompted us to analyze the case. To the best of our knowledge, an AC accompanying OM has not been reported. The pathogenesis and management of the case will be discussed.