What Is a Tarlov or Perineural Cyst on a Spine MRI?

Short answer: a Tarlov cyst, also called a perineural cyst, is a fluid-filled cyst near a nerve root, often in the sacral area. Many are incidental, but some deserve closer review depending on size, location, and symptoms.

What the wording usually describes

The key question is whether symptoms match the cyst location and whether other more common pain sources are present. A cyst seen on MRI should be interpreted with the exam and the full imaging report.

Details that make the finding more or less important

where the cyst is located and how large it is
whether there is nerve compression or bone remodeling described
whether pain, numbness, bladder/bowel symptoms, or sitting intolerance match the region
whether other findings such as stenosis, disc disease, or SI-joint issues are more plausible
whether symptoms are stable, improving, or worsening

How to discuss it at a pain visit

Ask what features make the cyst likely incidental versus clinically relevant. New bladder or bowel changes, progressive weakness, or severe neurologic symptoms should be reviewed urgently.

Related PSG resources: lower back pain, sciatica, and sacroiliac joint pain.

Sources include NCBI StatPearls - Tarlov Cyst, RadiologyInfo - MRI Spine, NINDS - Low Back Pain Fact Sheet. This article is educational and cannot diagnose the cause of pain from an imaging phrase alone.

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