Description

A 4-year-old male child presented to the emergency department after a first seizure. He recently had frequent headaches and consciousness disorders. Magnetic resonance imaging of the brain revealed an arachnoid cyst, measuring 5.0 cm by 9.0 cm by 8.2 cm, lateralized on the left. The cyst is responsible for an elevation of the tentorium of the cerebellum, a mass effect on: fourth ventricle, aqueduct of Sylvius and midbrain diencephalic structures and causing a moderate upstream responsible for upstream protected hydrocephalus with no sign of trans-ependymal resorption. The left cerebellar hemisphere and the verm is were shifted to the right of midline by 7 mm. Arachnoid cysts are congenital malformations containing cerebrospinal fluid. Usually, there are asymptomatic and are considered benign incidental finding on imaging. In some case, such as ours, the cyst can take an immense size becoming symptomatic due to mass effect. Although fenestration through craniotomy is the most frequently adopted first-line treatment, a more conservative approach was decided in our case. The patient underwent a microscopic fenestration via a craniotomy in order to release the cyst compression and restore the intracranial pressure. Post -operative imaging showed a significant downsize of the cyst. The symptoms have subsidized and antiepileptic therapy has been prescribed using preventive doses to manage eventual seizures (FIgure 1).

Figure 1:

References

1. de Longpre J. Large Arachnoid Cyst. N Engl J Med. 2017; 376: 2265.
2. Makino K, Tsutsumi S, Takaki Y, Nonaka S, Okura H, Ishii H. An infantile case of posterior fossa arachnoid cyst presenting with marked engorgement of contral ateral supraorbital vein. Radiol Case Rep. 2021; 16: 3680-3684.