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Benign Spinal Lesions & Cysts
Perineural Cyst
An in-depth, evidence-based guide to perineural cysts of the spine — fluid-filled sacs that form around nerve roots, why most cause no trouble, and how the minority that do are assessed and treated.
A perineural cyst is a fluid-filled sac that develops around a spinal nerve root, most often where the nerve leaves the spinal canal. The cyst is filled with the same cerebrospinal fluid that surrounds the nerves, and it forms in the sleeve of tissue that wraps the nerve root. Perineural cysts are common, and the great majority are found by chance on scans done for other reasons and never cause any symptoms at all. Occasionally, however, a cyst grows large enough to press on the nerve it surrounds, and then it can cause pain or other nerve symptoms. This page explains what these cysts are, why most need no treatment, and how the small number that do cause problems are assessed.
For information only — not medical advice. The content on this page is patient education to help you understand a condition or treatment. It is not a substitute for personalised assessment by a qualified clinician. Always consult your doctor or specialist about your own symptoms, diagnosis, and treatment decisions.
What perineural cysts are and why most cause no symptoms
Perineural cysts arise in the sleeve of the nerve root, between two layers of the lining that surrounds the nerve. Because they are so often symptomless, the most important message is one of reassurance: finding a perineural cyst on a scan is usually an incidental discovery of no consequence, and it does not mean you need treatment. The challenge, when symptoms are present, is to work out carefully whether they are genuinely caused by the cyst or by something else, such as a disc problem or ordinary wear, because treating a cyst that is not actually responsible will not help.
When a perineural cyst causes symptoms
When a cyst does become symptomatic, it is usually because it has enlarged and is pressing on its nerve root or on nearby structures. Symptoms depend on which nerve is involved and can include pain in the back or buttock, pain radiating into the leg, and sometimes altered sensation, or bladder, bowel or sexual symptoms when sacral nerves are affected. Symptoms that worsen on standing and ease on lying down are sometimes described. Careful assessment — a detailed history, examination, and MRI — is used to decide whether the cyst is the true source of the trouble.
How symptomatic perineural cysts are assessed and treated
Most people with perineural cysts need no treatment at all, and simple measures for the symptoms are the sensible first step. Where a cyst is confidently shown to be the cause of significant, persistent symptoms, treatment options exist and are considered carefully and individually. These range from image-guided procedures, such as aspirating the cyst or injecting fibrin sealant, through to surgery to decompress and repair the cyst, and the evidence shows that carefully selected treatment can relieve symptoms in the right patients. Because these are uncommon problems and the results depend heavily on choosing the right person, the decision is always made cautiously and only when the cyst is genuinely responsible for the symptoms.
Outlook
For the overwhelming majority of people, a perineural cyst is a harmless incidental finding that needs nothing more than reassurance. For the small number with genuinely symptomatic cysts, careful assessment and appropriately chosen treatment can improve symptoms, though as with any intervention there are risks and no guarantee of complete relief. My priority is to distinguish the cyst that truly matters from the far more common one that does not, and to avoid unnecessary treatment.
The information provided on this page is intended for educational purposes only and should not be considered personalised medical advice. Every patient is different, and treatment options, risks, expected recovery and outcomes depend upon an individual's diagnosis, general health and personal circumstances. Decisions regarding treatment should always be made following consultation with your treating spinal surgeon or healthcare professional.
Evidence & further reading
- —Paredes Mogica JA, et al. Sacral Tarlov perineurial cysts: a systematic review of treatment options. J Neurosurg Spine 2024. (PMID 38100766)
- —Murphy K, et al. Treatment of 213 patients with symptomatic Tarlov cysts by CT-guided percutaneous fibrin sealant. AJNR Am J Neuroradiol 2016. (PMID 26405086)
- —Burke JF, et al. Microsurgical treatment of sacral perineural (Tarlov) cysts: case series and review. J Neurosurg Spine 2016. (PMID 26745352)
- —Elsawaf A, et al. Surgical excision of symptomatic sacral perineural Tarlov cyst: case series and review. Eur Spine J 2016. (PMID 27154168)
- —Tanaka M, et al. Surgical results of sacral perineural (Tarlov) cysts. Acta Med Okayama 2006. (PMID 16508691)
- —Tracz J, et al. Interventional approaches to symptomatic Tarlov cysts: a 15-year institutional experience. J Neurointerv Surg 2024. (PMID 37402574)
- —Feigenbaum F, et al. Prospective validation of the Tarlov Cyst Quality of Life Scale. World Neurosurg 2022. (PMID 35700862)
- —Tani S, et al. Prevalence of spinal meningeal cyst in the sacrum. Neurol Med Chir (Tokyo) 2013. (PMID 23438659)
- —Konar SK, et al. Isadore Max Tarlov and the controversial Tarlov cyst: historical perspective. J Neurosurg Spine 2016. (PMID 26516664)
- —Jung KT, et al. Clinical experience of symptomatic sacral perineural cyst. Korean J Pain 2012. (PMID 22787551)
- —Yang AI, et al. Growth of a sacral perineural (Tarlov) cyst. World Neurosurg 2018. (PMID 30096508)
- —Ostojic P. Sacral perineural cyst mimicking inflammatory low back pain. Z Rheumatol 2015. (PMID 25315123)
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