Management of Incidentally Discovered Small Asymptomatic Tarlov Cysts
For incidentally discovered small asymptomatic Tarlov cysts, no routine follow-up or intervention is required—these are benign findings that can be safely observed without imaging surveillance.
Diagnostic Confirmation
When a Tarlov cyst is suspected on initial imaging, confirm the diagnosis with characteristic features:
- Deep cystic masses communicating with sacral foramina on ultrasound or MRI 1
- Location in the sacral region along nerve root sheaths
- MRI or CT myelography can demonstrate communication with the spinal subarachnoid space 2
The ACR Appropriateness Criteria explicitly classify Tarlov cysts among benign adnexal/pelvic lesions that can be accurately diagnosed by their characteristic imaging features 1.
Management Algorithm for Asymptomatic Small Tarlov Cysts
No Intervention Required
The vast majority of Tarlov cysts are incidental findings that are clinically unimportant 3. Research demonstrates that most Tarlov cysts (approximately 70% in one series of 54 patients) cannot be held responsible for patients' symptoms 3.
Key management principles:
- No routine imaging follow-up is necessary for asymptomatic cysts
- No surgical intervention indicated
- Document the finding in the medical record for future reference
- Reassure the patient that this is a benign anatomic variant
When to Reconsider (Red Flags)
Re-evaluate only if the patient develops:
- New radicular pain (back pain, coccyx pain, lower extremity pain)
- Neurological symptoms (leg weakness, sensory changes)
- Bowel/bladder dysfunction
- Sexual dysfunction
These symptoms warrant correlation with cyst size and location 4, 2.
Evidence Quality and Rationale
The ACR guidelines 1 provide the highest quality evidence, explicitly categorizing Tarlov cysts as benign lesions with characteristic imaging features that do not require intervention when asymptomatic. This is reinforced by multiple research studies demonstrating that:
- Tarlov cysts are found in approximately 1.5-9% of the population on imaging 5
- The majority are asymptomatic incidental findings 4, 3
- Asymptomatic cysts do not require treatment by consensus 4, 2
Common Pitfalls to Avoid
Over-imaging: Do not order serial MRI surveillance for small asymptomatic cysts—this increases cost and patient anxiety without clinical benefit
Misdiagnosis on ultrasound: Tarlov cysts can be mistaken for hydrosalpinges or ovarian cysts on pelvic ultrasound 6. Look for the characteristic communication with sacral foramina to distinguish them
Unnecessary referrals: Do not refer asymptomatic patients to neurosurgery—surgical intervention is controversial even for symptomatic cysts and carries significant morbidity risk 4, 7
Attributing unrelated symptoms: If a patient has symptoms, carefully determine whether the cyst location and size could plausibly explain them. In one series, 9 patients had Tarlov cysts at the same level as other pathology, and treating the other pathology resolved symptoms 3
Size Considerations
While the guidelines don't specify exact size thresholds for Tarlov cysts, the research literature suggests:
- Small cysts (typically <1.5 cm) are almost universally asymptomatic
- Larger cysts may be more likely symptomatic, but size alone does not mandate intervention 5, 7
The critical factor is symptom presence, not cyst size.
Documentation
Document in the radiology report and clinical notes:
- Location and size of the cyst
- Communication with sacral foramina
- Absence of symptoms
- No follow-up imaging required
This prevents future confusion and unnecessary repeat imaging when the finding is rediscovered on subsequent scans performed for other indications.