A 67-year-old man presented with persistent penis and scrotum pain due to S-2 and S-3 radiculopathy caused by a sacral perineural cyst. The cyst was treated with microsurgical partial cyst removal and cyst wall imbrication, together with closure of the point through which cerebrospinal fluid (CSF) flowed from the subarachnoid space into the cyst cavity. His pain resolved without recurrence of the cyst or complications. Symptomatic perineural cysts are quite rare. Surgical closure of the point through which CSF flows from the subarachnoid space into the cyst cavity is the most important intervention for symptomatic perineural cysts. If the source of CSF leakage cannot be detected, placement of a cyst-subarachnoid shunt should be considered in addition to partial cyst removal and cyst wall imbrication.