Perineural cysts, also known as Tarlov cysts, are rare benign cerebrospinal fluid-filled cysts usually located at the junction of the posterior nerve root and the dorsal root ganglion and are usually asymptomatic. They are most commonly found in the sacral region and are uncommon in the cervical spine. Despite their rarity, symptomatic cases may present with neurological symptoms due to the compression of adjacent neurological structures. Symptomatic cervical perineural cysts are extremely rare, and there is limited consensus on management strategies. We present the case of a 56-year-old woman who presented with a four-week history of radicular symptoms involving the right C7 and C8 nerve roots, including neck and arm pain, paresthesias, and mild triceps weakness. Magnetic resonance imaging revealed two perineural cysts at the C6-C7 and C7-T1 levels. A conservative approach was chosen with a 14-day course of oral corticosteroids, use of a soft collar, and activity restrictions. Following this conservative treatment, a significant reduction in symptoms and complete neurological recovery were achieved. This case highlights the efficacy of conservative approaches in selected cases of mildly symptomatic cervical perineural cysts and contributes to a better understanding of management strategies for this condition.

Tarlov cysts, also known as perineural cysts, are usually associated with lumbar discomfort and neurological deficits, with an uncertain etiology that may involve genetic predisposition and collagen disorders, possibly influenced by traumatic events and hemorrhagic episodes. Diagnostic methods such as magnetic resonance imaging or computed tomography myelography are commonly employed and treatment approaches range from conservative measures to more invasive interventions. This case involves a 42-year-old female with cervical pain and upper limb symptoms; a comprehensive assessment, including diagnostic imaging and physiotherapeutic interventions, resulted in significant improvements in pain intensity, range of motion, manual muscle testing, and functional scale scores after a two-week physiotherapy intervention. These findings contribute to advancing our understanding of managing Tarlov cysts associated with cervical radiculopathy, highlighting the potential efficacy of physiotherapeutic interventions in enhancing patient outcomes.

OBJECTIVE: Tarlov cysts (TCs) are dilated nerve root sheaths originating from increased cerebrospinal pressure. Patients with TCs often complain of neuropathic pain and paresthesia. The aim of this study was to retrospectively review intraepidermal nerve fiber density (IENFD) and electrodiagnostic (EDX) data from TC patients.
METHODS: Lower leg skin biopsy results and EDX data from the L2-S4 myotomes of patients with lumbar or sacral TCs ≥8 mm were retrieved from a database of a physical medicine clinic. Patients with compressive pathology, diabetes mellitus and chemotherapy were excluded.
RESULTS: IENFD data from 17 patients and EDX data from 24 patients with TCs ≥8 mm were available. The mean age was 47 ± 10y, and 83% were women. In 82% of patients, the IENFD was below the 5th percentile by age and sex. EDX showed increased Hoffmann reflex latencies in 25%, increased anal reflex latencies in 95%, and a patchy distribution of neurogenic motor unit potentials in 100%. More than 50% of needle EMG abnormalities appeared in myotomes unrelated to the location of the TCs.
CONCLUSIONS: Small- and/or large-fiber neuropathy was documented in a significant proportion of patients with TCs. The novel findings may add to the understanding of the mechanisms involved in symptomatic TCs. We propose that pathologically elevated cerebrospinal fluid pressure not only dilates some of the nerve root sheaths to form TCs but also potentially damages axons in nondilated nerve root sheaths and neurons in the dorsal root ganglia.

Pudendal neuralgia is a painful neuropathic condition involving the pudendal nerve dermatome. Tarlov cysts have been reported in the literature as another potential cause of chronic lumbosacral and pelvic pain. Notably, they are often located in the distribution of the pudendal nerve origin at the S2, S3, and S4 sacral nerve roots and it has been postulated that they may cause similar symptoms to pudendal neuralgia. Literature has been inconsistent on the clinical relevance of the cysts and if they are responsible for symptoms.
To evaluate the prevalence of S2-S4 Tarlov cysts at the pudendal nerve origin (S2-S4 sacral nerve roots) in patients specifically diagnosed with pudendal neuralgia, and establish association of patient symptoms with location of Tarlov cyst.
A retrospective study was performed on 242 patients with pudendal neuralgia referred for pelvic magnetic resonance imaging from January 2010 to November 2012. Dedicated magnetic resonance imaging review evaluated for presence, level, site, and size of Tarlov cysts. Among those with demonstrable cysts, subsequent imaging data were collected and correlated with the patients\' clinical site of symptoms. Statistical analysis was performed using χ2, Pearson χ2, and Fisher exact tests to assess significance.
Thirty-nine (16.1%) patients demonstrated at least 1 sacral Tarlov cyst; and of the 38 patients with complete pain records, 31 (81.6%) had a mismatch in findings. A total of 50 Tarlov cysts were identified in the entire patient cohort. The majority of the Tarlov cysts were found at the S2-S3 level (32/50; 64%). Seventeen patients (44.7%) revealed unilateral discordant findings: unilateral symptoms on the opposite side as the Tarlov cyst. In addition, 14 (36.8%) patients were detected with bilateral discordant findings: 11 (28.9%) had bilateral symptoms with a unilateral Tarlov cyst, and 3 (7.9%) had unilateral symptoms with bilateral cysts. Concordant findings were only demonstrated in 7 patients (18.4%). No significant association was found between cyst size and pain laterality (P = .161), cyst volume and pain location (P = .546), or cyst size and unilateral vs bilateral pain (P = .997).
The increased prevalence of Tarlov cysts is likely not the etiology of pudendal neuralgia, yet both could be due to similar pathogenesis from part of a focal or generalized condition.

Perineural cysts are sometimes found incidentally with magnetic resonance imaging, and clinical symptoms requiring treatment are rare. Perineural cysts typically exhibit delayed filling with contrast medium on myelography, which is one of the criteria used by Tarlov to distinguish perineural cysts from meningeal diverticula. We present a case of multiple thoracolumbar perineural cysts, one of which was considered the cause of intermittent intercostal neuralgia with atypical findings on postmyelographic computed tomography seen as selective filling of contrast medium.
A 61-year-old woman presented with intermittent pain on her left chest wall with distribution of the pain corresponding to the T10 dermatome. Magnetic resonance imaging showed multiple thoracolumbar perineural cysts with the largest located at the left T10 nerve root. On postmyelographic computed tomography immediately after contrast medium injection, the largest cyst and another at left T9 showed selective filling of contrast medium, suggesting that inflow of cerebrospinal fluid to the cyst exceeded outflow. Three hours after the injection, the intensity of the cysts was similar to the intensity of the thecal sac, and by the next day, contrast enhancement was undetectable. The patient was treated with an intercostal nerve block at T10, and the pain subsided. However, after 9 months of observation, the neuralgia recurred, and the nerve block was repeated with good effect. There was no recurrence 22 months after the last nerve block.
We concluded that intermittent elevation of cerebrospinal fluid pressure in the cyst caused the neuralgia because of an imbalance between cerebrospinal fluid inflow and outflow, and repeated intercostal nerve blocks resolved the neuralgia. Our case demonstrates the mechanism of cyst expansion.

OBJECTIVE: To determine the prevalence of simple and complex sacral perineural Tarlov cysts (TCs) in a cohort of children and adults.
METHODS: Retrospective observational epidemiological study assessing 1100 consecutive sacral magnetic resonance (MR) studies, including 100 children and adolescents. All patients underwent 1.5T MR imaging with T1 and T2 weighted image acquisitions in sagittal and axial planes. All perineural cysts affecting the sacral nerve roots S1-S4 were quantitatively and qualitatively assessed.
RESULTS: Two hundred and sixty-three sacral TCs were found in 132 adult patients (13.2%), with a female predominance (68%). None was found in children. The prevalence of TCs increased with age. The average number of cysts per patient was 2.0±1.2 with a maximum of 6 cysts in a single patient. Most of the cysts (87.5%) showed a homogenous central fluid collection and a parietal course of the nerve fibers. Complex patterns were present in 33 cysts (12.5%) within which 28 cysts showed endocystic crossing of nerve fibers and 5 cysts contained internal septations. Seventy cysts (26.6%) eroded the adjacent bone and 13 cysts (4.9%) extended to the pelvis.
CONCLUSIONS: The prevalence of sacral TCs in our cohort corresponded to 13%, with a female predominance. Interestingly no TCs were found in children or adolescents (<18 years). In relation to the non-negligible percentage of complex cysts with internal septations, or endocystic crossing of nerve fibers, pre-interventional characterization of sacral TCs might help to choose an appropriate procedure in the treatment of rare symptomatic variants.