Introduction: Tarlov (perineural) cysts of the nerve roots are common and usually incidental findings during magnetic resonance imaging of the lumbosacral spine. There are only a few case reports where thoracic symptomatic perineural cysts have been described in the literature. We report a case where a high thoracic perineural cyst was masquerading as a nerve root sheath tumor.

Methods: Our patient is a 39 year old white female with presented with 5 weeks of progressive severe left upper extremity pain, radicular in nature, with new onset left hand weakness. MRI cervical spine showed left sided T1 nerve root cystic lesion with extension into the neuroforamen. The patient underwent left sided T1-T2 partial laminectomy with facetectomy with excision of the cyst, followed by C7 - T3 posterior instrumented fusion.

Results: Our patient experience complete resolution of her symptoms on post op day 1, the procedure also helped in reducing the patient pain medication requirement. There were no surgical complications noted. Pathology results confirmed perineural cyst.

Conclusions: Thoracic spine perineural cysts are rare and usually misdiagnosed as nerve sheath tumor, surgical excision of these cysts can result in significant improvement in patients symptoms and improvement in quality of life.

Patient Care: This case report will increase awareness of thoracic nerve root perineural cysts, it shows that surgical excision of there cysts can result in significant improvement of patient symptoms and quality of life.

Learning Objectives: 1. Tarlov Cysts can involve thoracic nerve roots. 2. It can be misdiagnosed as nerve root sheath tumor. 3. It can cause severe radicular symptoms. 4. Surgical excision can result in complete resolution of symptoms.

References: 1. Acosta Jr, Quinones-Hinojosa A, Schmidt M, Weinstein P: Diagnosis and manage- ment of sacral Tarlov cysts. Case report and review of the literature. Neurosurg Focus, 2003 Aug 15;15(2):E15. 2. Cabot R, Harris N, Rosenberg E, Shepard J, Cort A, Ebeling S, et al: Case 7-2013. New England Journal of Medicine N Engl J Med, 368(9), 853-861. 3. Caspar W, Papavero L, Nabhan A, Loew C, Ahlhelm F: Microsurgical excision of symptomatic sacral perineurial cysts: a study of 15 cases. Surg Neuro 2003;59:101-6. 4. Joshi V, Zanwar A, Karande A, Agrawal A: Cervical Perineural Cyst Masquerading as a Cervical Spinal Tumor. Asian Spine J Asian Spine Journal, 8(2), 202. 5. Mcevoy S, Diluna M, Baird A, Duncan C: Symptomatic Thoracic Tarlov Perineural Cyst. Pediatric Neurosurgery Pediatr Neurosurg, 45(4), 321-323. 6. Mummaneni P, Pitts L, McCormack B, Corroo J, Weinstein P. Microsurgical treatment of symptomatic sacral Tarlov cysts: Neurosurgery 2000; 47:74-9. 7. Nabors M, Pait T, Byrd E, Karim N, Davis D, Kobrine A, Rizzoli H: Updated assessment and current classification of spi- nal meningeal cysts. J Neurosurg 1988;68: 366–377. 8. Sato K, Nagata K, Sugita Y: Spinal extradural meningeal cyst: correct radiological and his- topathological diagnosis. Neurosurg Focus 2002;13:ecp1. 9. Tarlov IM: Perineurial cysts of the spinal nerve roots: Arch Neurol Psychiat (Chic) 1938;40:1067–1074. 10. Tarlov IM: Spinal perineurial and meningeal cysts: J Neurol Neurosurg Psychiatry 1970; 33:833–843.