en Gamma Knife Radiosurgery Case report <p style="text-align: justify;"><strong>Background and Importance:</strong> Perineural cysts, also known as Tarlov cysts, are benign cysts of the spinal cord containing a collection&nbsp;of cerebrospinal fluid. They most frequently originate in the sacral spine and can be asymptomatic.<br> <strong>Case Presentation:</strong> We presented a 30-year-old woman who was referred to our clinic with an 8-month history of perianal paresthesia,&nbsp;slowly progressive lower back pain, pain in back of the left and right thigh, and a one-week history of bladder incontinence. Magnetic&nbsp;resonance imaging (MRI) done six months ago showed a large cyst with size of 74x40x22 mm in S1 from S4 of the spinal canal. The&nbsp;cyst was uncovered after laminectomy of S1 to S4. The cyst was aspirated, its neck ligated, and the dismissed portion was excised.&nbsp;The nerve roots were reserved intact. Postoperatively, the patient reported noticeable pain relief. At month 3, the patient&#39;s bowel and&nbsp;bladder control recovered. Sensation and deep reflexes were also normal.<br> <strong>Conclusion: </strong>A giant sacral Tarlov cyst and the development of associated radicular symptoms are powerfully associated with an&nbsp;outstanding outcome following surgery.</p> Huge, Tarlove Cyst, Sacral, Neurologic Deficit 30 33 http://irjns.org/browse.php?a_code=A-10-34-1&slc_lang=en&sid=1 Kaveh Haddadi کاوه حدادی 10031947532846003129 10031947532846003129 Yes MD, Assistant Professor, Department of Neurosurgery, Emam Hospital, Orthopedic Research Center, Mazandaran University of Medical Sciences, Sari, Iran Hamid Reza Ganjeh Qazvini حمیدرضا گنجه ای 10031947532846003130 10031947532846003130 No MD, Resident of Neurosurgery, Department of Neurosurgery, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Hassan Shayan Majd حسن شایان مجد 10031947532846003131 10031947532846003131 No MD, Resident of Neurosurgery, Department of Neurosurgery, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Mojtaba Saleh Ahangar مجتبی صالح آهنگر 10031947532846003132 10031947532846003132 No MD, Resident of Neurosurgery, Department of Neurosurgery, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran