Tarlov Cysts (Perineural Sacral Cysts)
Fluid-filled cysts on sacral nerve roots that can occasionally cause pelvic and leg pain
ICD-10: G96.198 · systemic condition
Tarlov cysts — also called perineural sacral cysts — are fluid-filled sacs that form on the nerve roots within the sacral spinal canal. They were first described by Dr. Isadore Tarlov in 1938 and are found incidentally on MRI in approximately 1–13% of spine imaging studies. Most Tarlov cysts are asymptomatic and discovered by accident when imaging is performed for another reason. However, symptomatic Tarlov cysts can compress sacral nerve roots and cause a characteristic constellation of pelvic, buttock, genital, and leg symptoms that are frequently misdiagnosed. The condition is significantly underdiagnosed because radiologists often do not report small cysts, and the symptoms mimic more common conditions such as sciatica or pelvic floor dysfunction.
1–13%
Tarlov cysts are found on 1–13% of sacral MRI studies, with the wide range reflecting differences in cyst size thresholds used for reporting.
Voyadzis JM et al., Journal of Neurosurgery (2001)80%
Symptomatic Tarlov cysts are significantly more common in women, who comprise approximately 80% of cases presenting for treatment.
North American Spine SocietySymptoms
- Buttock, pelvic, perineal, or genital pain — often burning, aching, or pressure-like
- Leg pain, numbness, or weakness (radiculopathy) from sacral nerve compression
- Urinary frequency, urgency, or difficulty emptying the bladder
- Bowel dysfunction — constipation or difficulty with bowel movements
- Sexual dysfunction in both men and women
- Pain that worsens with prolonged sitting, standing, or walking and improves with lying down
- Headache worsened by Valsalva maneuver (straining, coughing)
Causes & Risk Factors
- Congenital weakness in the arachnoid membrane allowing CSF to accumulate
- Trauma — a fall or injury may trigger cyst growth or symptom onset
- Increased cerebrospinal fluid pressure driving fluid into the cyst
- Inflammation from prior surgery or lumbar puncture
Imaging Findings
Imaging studies are commonly used to identify findings associated with this condition. Results vary by individual; a qualified spine specialist interprets findings in the context of a full clinical evaluation.
MRI
- Diagnostic hallmark: Sacral nerve root sleeve cysts with CSF signal (T1 low, T2 high) communicating with the subarachnoid space
- Posterior sacral foraminal widening from chronic cyst pressure on bone
- Displaced or compressed sacral nerve roots within the affected foramina
- Cysts typically at S2–S3, but can occur at S1 through S4
- Note: Incidental Tarlov cysts found in 4–9% of routine spine MRIs — most are asymptomatic
CT Scan
- Scalloping and remodeling of the posterior sacrum with smooth, corticated margins
- CSF-density fluid within the sacral foramen or presacral space
- CT myelography: cyst fills with contrast confirming communication with subarachnoid space
- No bony destruction (distinguishes from sacral tumor)
X-Ray
- Sacral foraminal enlargement or posterior sacral cortical thinning on AP view
- Often normal or subtly abnormal — MRI is the definitive modality
Who Is Commonly Affected
The following patterns are commonly associated with this condition based on published population studies. Individual presentation varies; these figures are informational only.
Peak Age Range
30–60 years at symptom onset
Gender Distribution
Female predominance, approximately 3:1
Estimated Prevalence
Incidental prevalence 4–9% on lumbar/sacral MRI; symptomatic cases are far rarer
Treatment Options
Conservative
- Observation and reassurance for asymptomatic cysts
- Pain management — NSAIDs, gabapentin, or tricyclic antidepressants for neuropathic pain
- CT-guided cyst aspiration and fibrin glue injection — minimally invasive, may provide temporary relief
- Pelvic floor physical therapy for bladder and bowel dysfunction
Surgical
- Microsurgical cyst fenestration or excision with nerve root preservation
- CSF cyst shunting procedures — rarely performed due to high recurrence rates
- Cyst occlusion with fibrin glue during microsurgical exploration
When to see a spine specialist
If you have been diagnosed with Tarlov cysts on imaging and experience pelvic, buttock, genital, or leg pain, bladder or bowel symptoms, or sexual dysfunction, evaluation by a spine specialist or neurosurgeon familiar with the condition is recommended. Because Tarlov cysts are frequently dismissed as incidental findings, advocating for symptom-focused evaluation with a specialist who has experience with perineural cysts is important.
Specialists Who Treat Tarlov Cysts (Perineural Sacral Cysts)
Find a specialist who treats tarlov cysts (perineural sacral cysts)
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Questions to Ask Your Doctor
Bring these questions to your next appointment about tarlov cysts (perineural sacral cysts).
- 1
Are my Tarlov cysts symptomatic, and how do my symptoms correlate with the cyst locations on MRI?
- 2
What is the size threshold at which my cysts are more likely to cause nerve compression?
- 3
Have other causes of my pelvic, sacral, or leg pain been ruled out before attributing them to the cysts?
- 4
What are the risks and success rates of surgical drainage or cyst fenestration at your institution?
- 5
Are there non-surgical options — such as CT-guided aspiration with fibrin glue — that might help first?
Research Evidence
No studies reviewed yet for this condition. Check back soon — our evidence pipeline runs nightly.
Clinical Evidence
Key Research
- L4A systematic review of the efficacy of surgical intervention in the management of symptomatic Tarlov cysts
- L4Tarlov cysts and sexual dysfunction: A multidisciplinary approach to evaluation and surgical treatment
- L4Health-Related Quality-of-Life Outcomes in Surgical Patients With Sacral Tarlov Cysts: A 2-Year Prospective Study
- L4Interventional approaches to symptomatic Tarlov cysts: a 15-year institutional experience
Frequently Asked Questions
Are Tarlov cysts the same as cysts on the spine?
Tarlov cysts are a specific type of spinal cyst — perineural cysts arising from the nerve root sleeve at the sacral level. They are distinct from other spinal cysts such as synovial cysts (arising from facet joints), arachnoid cysts (arising from the arachnoid membrane but not nerve-root associated), or epidermoid cysts. The nerve-root involvement and sacral location of Tarlov cysts distinguish them clinically and radiographically.
How are Tarlov cysts diagnosed?
MRI of the sacrum and lumbar spine is the primary diagnostic tool. On MRI, Tarlov cysts appear as fluid-intensity lesions in the sacral canal, typically at S2–S4 levels. Dynamic MRI in sitting and standing positions can demonstrate communication with the CSF space and assess for cyst enlargement. CT myelography — injection of contrast into the CSF — definitively identifies communication with the subarachnoid space, which is a distinguishing feature of true Tarlov cysts.
Is there a cure for Tarlov cysts?
There is no universally reliable cure. Most symptomatic patients require multimodal management combining pain medications, targeted injections, and pelvic floor rehabilitation. CT-guided fibrin glue injection provides temporary relief in 50–60% of patients. Microsurgical treatment (cyst fenestration) has the best evidence for durable relief in carefully selected patients, but outcomes are variable and surgery carries risk of worsening sacral nerve dysfunction. Most patients achieve symptom control rather than complete resolution.