Title: Rapidly progressing myelopathy associated with intradural arachnoid cyst presenting with thoracic axial pain: case report  

Authors: Francesco Sammartino, Kathryn Slaughter, Jordan Bozer, Kristen Noon. 

Introduction (75 words) 

Spinal intradural arachnoid cysts (SIACs) are cerebrospinal fluid (CSF)-filled sacs originating from the arachnoid membranes, and they are most commonly located in the thoracic region. These cysts may be idiopathic or acquired, with the latter often developing secondary to trauma or other inflammatory events causing meningeal adhesions. Only about 20–30% of thoracic intradural arachnoid cysts are symptomatic. We present a case of a thoracic intradural cyst presenting with chest pain and progressive myelopathic symptoms. 

Materials and methods (150 words) 

The case report is devoid of patient-identifiable information, and it is exempt from IRB review requirements as per The Ohio State University policy. Consent for publication was obtained from the patient . 

Results / Case report (200 words) 

A 37-year-old female with Ehlers-Danlos syndrome presented in July 2024 with progressive mid-back pain. She reported sharp, radiating thoracic pain with paraspinal tenderness, improved with rest, without motor or sensory deficits. Thoracic x-rays showed degenerative changes suggestive of facet-arthropathy, which, in addition to myofascial pain, was supported by physical exam. She was referred to physical therapy and started on Lyrica, which yielded a self-reported 90% improvement by November. 

Her symptoms recurred after Lyrica was held during a 5-day hospitalization in December. By March, symptoms progressed to include chest wallparesthesias, imbalance, and urinary incontinence. Thoracic MRI revealed an arachnoid cyst anteriorly displacing the spinal cord at T5-T8. This prompted neurosurgical evaluationbut no intervention was offered at this time. 

By June 2025, she experienced debilitating gait instability and limb weakness, requiring a cane for ambulation. She presented to the ED with worsening symptoms and repeat thoracic MRI demonstrate cord flattening from the cyst and multiple dorsal intrathecal AVMs, later identified as flow void artifacts.CT-myelogram showed communication of the cyst with the subarachnoid space. She was deemed a surgical candidate for T4–T8 laminoplasty with cyst fenestration due to severe cord compression and myelopathy. 

Discussion (75 words) 

This case is relevant for several reasons. Thoracic pain is not a usual presentation for SIACs as >80% of cases are incidentally discovered2. This patient had only intermittent paresthesia of the chest wall which could have been an early sign of radiculopathy.Lastly, the relatively rapid progression of symptoms to dorsalgia associated with myelopathy is atypical3. While there is no documented evidence, the connective tissue disorder (Ehlers-Danlos) may be a predisposing factor for this course1.  

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