Tarlov cysts, also called perineural cysts, are CSF filled dilatations of the nerve root sheath at the dorsal root ganglion (posterior nerve root sheath). These are type II spinal meningeal cysts that are, by definition, extradural but contain neural tissue.
They occur in ~5% of the population, more commonly in women.
They have been occasionally associated in patients with connective tissue disorders:
The prevalence and severity of symptoms in patients with Tarlov cysts is controversial. Traditionally, and still largely the dominant view, it has been believed that like other spinal meningeal cysts, most Tarlov cysts are incidentally found and are asymptomatic. In some patients it appears that Tarlov cysts are the cause of symptoms, such as perineal pain/discomfort or lower back pain or sphincter/sexual dysfunction 3. Large cysts may cause local pressure effect and remodel bones. However, symptoms don't appear to correlate well with size 2.
While they are most common in the lower lumbar spine and in the sacrum, they can occur anywhere in the spine.
Most Tarlov cysts appear as CSF intensity simple cystic structures closely related to sacral and lower lumbar nerves.The sacral foramina may be widened. Morphology can vary from a simple rounded cyst to a complex loculated cystic mass.
History and etymology
It was initially described by I M Tarlov in 1938 1.
Usually, the diagnosis is self-evident and no alternatives should be entertained. Occasionally appearances are atypical and possible differential considerations include:
- 1. Tarlov IM. Perineural cysts of the spinal nerve roots. Arch Neurol Psychiatr 1938; 40:1067-1074.
- 2. Davis SW, Levy LM, Lebihan DJ et-al. Sacral meningeal cysts: evaluation with MR imaging. Radiology. 1993;187 (2): 445-8. Radiology (abstract) - Pubmed citation
- 3. Marino D, Carluccio MA, Di Donato I et-al. Tarlov cysts: clinical evaluation of an italian cohort of patients. Neurol. Sci. . doi:10.1007/s10072-013-1321-0 - Pubmed citation
- 4. Paulsen RD, Call GA, Murtagh FR. Prevalence and percutaneous drainage of cysts of the sacral nerve root sheath (Tarlov cysts). AJNR Am J Neuroradiol. 1994;15 (2): 293-7. Pubmed citation
- 5. Arnold PM, Teuber J. Marfan syndrome and symptomatic sacral cyst: report of two cases. J Spinal Cord Med. 2013;36 (5): 499-503. doi:10.1179/2045772312Y.0000000079 - Free text at pubmed - Pubmed citation