A sacral perineural cyst is composed of an arachnoid membrane of the nerve root at the sacral region. We performed a wide posterior decompression and cystectomy in a patient who suffered from back pain with pain radiating in both lower extremities, and whose MRI findings coincided with those of a sacral perineural cyst. Clinical improvement was observed during the follow-up review. We report the surgical treatment with a review of the relevant literature.