Abstract

An arachnoid cyst is a benign, space-occupying lesion which contains cerebrospinal fluid. Clinical manifestations may vary according to the size of the cyst and the interaction between the surrounding neuronal structures. Mental disorders rarely accompany the clinical picture and most of the cases remain symptom-free unless determined by radiological examinations accidentally. Although there are some cases reported on the comorbidity of psychosis and arachnoid cysts, no case has been reported on the comorbidity of bipolar disorder and arachnoid cysts so far. In this case report, a male patient with bipolar disorder and an arachnoid cyst in occipital lobe located in posterior fossa is presented and discussed in light of literature.

Key words: arachnoid cyst, bipolar disorder, occipital lobe.