Disclosures: Evan M. Berlin, MD: No financial relationships or conflicts of interest

Case Diagnosis: Tarlov Cyst

Case Description: 23-year-old male with no pertinent PMH presented to clinic with a 1.5-year history of progressive axial low back pain with no inciting event. He described the pain as “pressure”, localized it to the sacrum, and reported it intermittently felt like it was “bulging out”. Prolonged sitting, walking and working as a mechanic aggravated the pain, and rest alleviated it. He denied any radicular symptoms or any changes in bowel or bladder control. Over the counter anti-inflammatory medications provided minimal relief. He had performed PT with no relief. On exam, there was tenderness to palpation at the sacrum and pain was reproduced on range of motion testing with extension and lateral rotation. He was neurologically intact. MRI of the lumbar spine revealed an 8.8 cm x 7.2 cm x 3.7 cm perineural cyst filling nearly the entirety of the sacral spinal canal with associated canal expansion.

Discussion: Perineural cysts, also known as Tarlov cysts, are meningeal dilatations of the posterior nerve root sheath that most frequently occur in the sacral region and communicate with the cerebrospinal fluid. These cysts are usually asymptomatic and are discovered incidentally. However, sometimes the cyst can enlarge via net inflow of cerebrospinal fluid resulting in distortion, stretching, or compression of adjacent nerve roots, which can cause a progressively painful radiculopathy as well as localized pain via mass effect. Diagnosis is most often made by lumbosacral MRI imaging. On plain films, sacral foramina can appear enlarged.

Setting: Outpatient ClinicAssessment/

Results: n/a

Conclusion: Treatment is usually not required for asymptomatic Tarlov cysts. When symptomatic, the role of specific surgical and nonsurgical interventions remains controversial. Surgical intervention may include resection with or without fibrin gel injection, however the research and outcomes studies in cases such as this have been poorly documented. Risks of surgical intervention include worsening neurological deficits.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/tarlov-cyst-an-uncommon-cause-of-axial-low-back-pain/