# Arachnoid Web With Atypical Imaging Findings and Clinical Manifestations: A Case Report

## TL;DR

A 63-year-old man with a rare spinal arachnoid web showed unusual symptoms and MRI features, leading to successful surgical treatment.

## Contribution

This case highlights atypical imaging and clinical features of spinal arachnoid web, aiding in its diagnosis.

## Key findings

- MRI showed spinal cord atrophy and a dorsal flow void without the scalpel sign, indicating SAW.
- Surgical resection improved some symptoms, but numbness and bladder dysfunction remained.
- Asymmetric CSF pressure from the septum posticum may cause Brown-Sequard syndrome.

## Abstract

Spinal arachnoid web (SAW) is a rare intradural lesion that can result in spinal cord compression and myelopathy. This report describes a case of SAW with atypical imaging findings and clinical manifestations in a 63-year-old male patient who presented with progressive lower limb paresthesia and left-dominant muscle weakness. The patient also exhibited temperature and pain sensory disturbances in the right leg. Magnetic resonance imaging (MRI) revealed spinal cord atrophy, intramedullary hyperintensity, and a dorsal flow void without the scalpel sign at the T7 level. Laminectomy and surgical resection of the SAW were performed. Intraoperative ultrasound revealed a SAW obstructing the flow of cerebrospinal fluid (CSF). The left and right sides of the posterior space were divided by the septum posticum, which moved pulsatile from side to side. Postoperative improvements in muscle strength, temperature, and pain sensation were observed; however, numbness and bladder dysfunction persisted. Diagnosing SAW is challenging in the absence of the scalpel sign; however, in cases of spinal cord atrophy and a dorsal CSF flow void on MRI, the presence of SAW should be considered. Brown-Sequard syndrome may result from asymmetric CSF pressure caused by the septum posticum.