Dorsal arachnoid web of the thoracic spine associated with an arachnoid cyst and a presyrinx state as an unexplained cause of thoracic myelopathy: illustrative case.

BACKGROUND: Dorsal thoracic arachnoid web is a rare diagnosis and is not commonly seen in neurosurgical practice. Patients can present with symptoms and signs of thoracic myelopathy in the setting of an arachnoid cyst and a presyrinx state. OBSERVATIONS: A 57-year-old male with a 10-year history of worsening bilateral leg weakness and chronic back pain re-presented to the neurosurgery clinic after being seen by neurology and orthopedic spine surgery. Initial imaging was concerning for myelomalacia and syringomyelia, and repeat delayed computed tomography myelography findings were consistent with an evolving thoracic arachnoid web, now demonstrating spinal cord compression secondary to arachnoid cyst formation and consistent with the signs of thoracic myelopathy. Intraoperative ultrasound displayed the arachnoid web as the cause of the evolving arachnoid cyst, edematous spinal cord, and a presyrinx-like state. The patient underwent surgical decompression, which restored cerebrospinal fluid (CSF) dynamics, resulting in clinical improvement. LESSONS: Dorsal thoracic arachnoid web is a dynamic condition that can occur in the setting of an arachnoid cyst. There appears to be a relationship between dorsal thoracic arachnoid web formation and the presence of an arachnoid cyst resulting from a ball-valve mechanism leading to the creation of a pressure gradient effect that alters CSF fluid dynamics. https://thejns.org/doi/10.3171/CASE24313.

Double inversion recovery to detect cervical spinal cord multiple sclerosis lesions.

BACKGROUND AND PURPOSE: Magnetic resonance imaging (MRI) plays a key role in diagnosing and monitoring multiple sclerosis (MS). Double inversion recovery (DIR) is a pulse sequence that has proven highly effective at detecting cortical lesions but is understudied in the spinal cord. We hypothesize that DIR images obtained during brain MRI can be of value in assessing the upper spinal cord of MS patients. METHODS: We retrospectively examined brain MRI exams of 64 patients with established MS, who had also undergone cervical spine MRI. Two blinded MS expert readers, who assessed the scans for lesion numbers and rated lesion visibility and overall image quality, reviewed brain 3-dimensional DIR sagittal and coronal images. Standardized mean contrast-to-noise ratios (C/N) and standard deviation (SD) were calculated in representative lesions for each patient and compared to those of 3-dimensional FLAIR images. RESULTS: For the analysis of lesions categorized as "definite lesions," the sensitivity was 87%, specificity was 61%, and negative predictive value was 80%. On the other hand, for "definite" plus "probable" lesions, the sensitivity was 91%, the specificity was 54%, and negative predictive value was 86%. DIR demonstrated lesions with an average C/N of 7.56 with an SD of 1.77. FLAIR sequence demonstrated lesions with an average C/N of 0.67 and SD of 1.27. CONCLUSIONS: Sagittally acquired brain DIR can provide useful information on upper spinal cord lesions, with high C/N. In theory, this should facilitate the attainment of McDonald's or the Magnetic Resonance Imaging in MS (MAGNIMS) criteria in some cases, without a dedicated cervical spine MRI exam.

Spinal Lymphoma Presenting as an Epidural and Retropleural Mass With Concomitant Pathologic Compression Fracture: A Case Report.

Lymphoma has traditionally earned the nickname "the great mimicker". Its presentation as a primary spinal tumor is rare, and therefore seldom included in the differential diagnosis. However, its mimicking nature and diverse presentation make it very difficult to exclude entirely. Here, we present an elderly patient with histology-confirmed spinal lymphoma presenting as both an epidural mass with transforaminal extension into the retropleural space as well as vertebral body compression fracture, together leading to severe spinal stenosis and compressive myelopathy. Additional non-malignant compression fractures found in our patient allow for an interesting discussion on disease presentation and imaging-based diagnosis. We discuss our approach to diagnosis, surgical treatment, and post-operative medical care.