What is a Perineural (Tarlov) Cyst of the Cervical Spine?
A perineural cyst (also called a Tarlov cyst) of the cervical spine is a rare, benign, cerebrospinal fluid-filled sac located at the junction of the posterior nerve root and dorsal root ganglion, with a wall composed of endoneurium, peripheral nerve fibers, ganglion cells, and areolar tissue 1.
Key Anatomical and Clinical Features
Location and Prevalence
- Cervical perineural cysts are extremely rare - these lesions occur most commonly in the sacral region, with cervical spine involvement being uncommon 2, 3
- Population prevalence ranges from 1.5-13.2%, with significant female predominance 1
- When found in the cervical spine, they typically occur at levels like C5-C6, C6-C7, or C7-T1 2, 3
Pathophysiology
The cyst develops through several potential mechanisms:
- Ischemia
- Hemorrhage
- Inflammation
- Trauma 1
Genetic predisposition and collagen disorders may also play a role 4.
Clinical Presentation
Symptomatic vs Asymptomatic
- Most perineural cysts are asymptomatic and discovered incidentally on imaging 1, 3
- Approximately 25% become symptomatic when the cyst exerts sufficient pressure on the nerve root and neighboring structures 1
When Symptomatic in the Cervical Spine
Patients present with radicular symptoms corresponding to the affected nerve root level:
- Neck and arm pain
- Paresthesias (numbness/tingling) in specific dermatomal distributions
- Weakness in corresponding myotomes (e.g., triceps weakness with C7-C8 involvement) 2
- Symptoms may worsen with fatigue or upon waking 5
- Duration typically ranges from weeks to months before diagnosis 2, 3
Diagnostic Approach
MRI of the cervical spine is the diagnostic modality of choice for identifying perineural cysts 2, 4, 3. The cysts appear as cerebrospinal fluid-filled lesions at the nerve root level. CT myelography can also be used but is less commonly employed 1.
Important Diagnostic Consideration
Cervical perineural cysts can masquerade as cervical spinal tumors on imaging, making accurate radiological interpretation critical 6. The differential diagnosis for patients with radicular symptoms should include perineural cysts 3.
Management Implications
Conservative Treatment (First-Line)
Conservative management is highly effective for mildly symptomatic cervical perineural cysts and should be the initial approach 2, 3:
- Soft cervical collar for 2 weeks
- Oral corticosteroids (14-15 day course) 2 or NSAIDs 3
- Activity restrictions and modification
- Physical therapy interventions 4
Outcomes with conservative treatment are excellent, with reports of 90% symptom improvement and complete neurological recovery in appropriately selected cases 2, 3.
Surgical Intervention
Surgery is reserved for:
- Failure of conservative treatment
- Progressive neurological deterioration
- Persistent, disabling symptoms
Surgical options include:
The percutaneous endoscopic approach has shown promising results with complete symptom resolution, no cerebrospinal fluid leakage, and no recurrence at 2-year follow-up 5.
Clinical Pitfalls
- Do not assume all cervical cystic lesions are tumors - perineural cysts must be in the differential, especially when radicular symptoms are present 6
- Avoid rushing to surgery - the natural history with conservative treatment is favorable in most symptomatic cases 2, 3
- MRI findings in asymptomatic patients are common - correlation with clinical symptoms is essential before attributing symptoms to the cyst 7