Author Affiliations: Department of Neurosurgery, Niigata City General Hospital, Niigata, Japan.
A 25-year-old woman without any significant medical or traumatic history presented with a 1-month episode of recurrent and progressive bioccipital headaches and nausea. At age 18 years, she had been investigated for occasional bitemporal headache in a local clinic, and a 1 × 1-cm retrocerebellar cyst had been incidentally detected on magnetic resonance imaging (Figure, A). The lesion was considered to be of no significance with regard to her symptoms at that time and thus was left untreated.
Kurabe S, Sasaki O, Mitsuhashi D, Koike T. Growing Posterior Fossa Arachnoid Cyst Causing Tonsillar Herniation and Hydrocephalus. Arch Neurol. 2011;68(12):1606-1607. doi:10.1001/archneurol.2011.749