What's Causing This Man's Low Back Pain?
A 66-year-old man with history of chronic low back pain presents with worsening pain and right-sided sciatic symptoms. Symptoms were partially relieved by anti-inflammatories, muscle relaxers, and analgesics.
On physical exam, the patient had mild low back muscle spasm, no saddle anesthesia, straightly leg test negative. Patient denied bowel or bladder dysfunction.
Plain films revealed moderate degenerative joint disease (DJD). MRI showed multilevel DJD with bilateral mild neuroforamen narrowing from L5 through S1 (Figures 1 and 2). Incidentally noted, was a 4 x 3 cm cystic structure in the distal aspect of the thecal sac.
What's Your Diagnosis?
A. Anterior sacral meningocele
B. Solitary neurofibroma
C. Giant sacral schwannoma
D. Perineurial (Tarlov) cyst
E. Sacrococcygeal teratoma
(Answer and discussion on next page)
Answer: TARLOV CYST
Tarlov cysts, also known as perineurial cysts or nerve root cysts, are rare cysts often found incidentally on imaging exams for spinal problems. These cysts are fluid-filled sacs, which are located between the endoneurium and the perineurim of the nerve root sheath near the root ganglion and affect the sacral area of the spine.1 The estimated incidence of Tarlov cysts in the adult population ranges from 4.6% to 9%.2 Tarlov cysts are distinguished from other spinal cysts by the hisopathological finding of nerve root fibers and ganglion cells.1
Most Tarlov cysts are asymptomatic; however, as the cysts enlarge, they are more likely to cause symptoms. The more common sensory symptoms are caused by dorsal root compression and motor symptoms by ventral root compression. Symptoms include low back pain, leg numbness or weakness, sciatic nerve pain, and bowel and bladder dysfunction.2 Rarely, Tarlov cysts can rupture either spontaneously or as a result of trauma. This would cause a cerebrospinal fluid leak (CSF)resulting in a severe headache relieved by laying supine.
Tarlov cysts can be identified through various imaging exams including CT, MRI, and CT myelogram.2
The treatment of Tarlov cysts remains controversial and includes nonsurgical and surgical options.1,2 Nonsurgical options include lumbar CSF drainage and percutaneous cyst aspiration with fibrin glue replacement.2 Surgical options include cyst removal, decompressive laminectomy, cyst resection, and placement of subarchanoid shunts.2 ■
Samia Holman, MSN, FNP-C, is a family nurse practitioner at the VA Long Beach Medical Center. She works at the primary care clinic.
Michael J. Kim, MD, is section chief of neuroradiology at the VA Long Beach Radiology Imaging Service and assistant clinical professor in the department of radiological sciences at the University of California Irvine Medical Center.
Farrukh Merchant, MD MHSA, is family physician and the section chief of primary care at the VA Long Beach Medical Center
References:
1. Chaiyabud, P, Suwanpratheep, K. Symptomatic Tarlov cyst: report and review. J Med Assoc Thai. 2006;89(1):1047-1050.
2. Acosta FL, Quinones-Hinojosa A, Schmidt MH, et al. Diagnosis and management of sacral Tarlov cysts. Neurosurg Focus. 2003;15(2):E15.