question: Hello doctor, My friend had giddiness, so he got an MRI scan. The report showed a well-defined cyst in the posterior fossa, dorsal to the cerebellum. It is an arachnoid cyst. It also states bilateral AICA lying at the level of the internal auditory canal without entering the meatus. Type 1 AICA vascular loops. I do not understand the report. Please help. Since a cyst is mentioned in the report, can it be cured by medicine? How did my friend get this cyst in the brain? And why did he get it? Is it due to drinking alcohol?