A 36-year-old man with chronic back pain

A 36-year-old man with chronic back pain

A

B

What is your diagnosis?

A 36-year-old man with chronic back pain

The answer is Arachnoid Webs

Arachnoid webs are intradural extramedullary bands of arachnoid tissue that can extend to the pial surface of the spinal cord, causing a focal dorsal indentation of the cord, known as "scalpel sign" (arrow in A) and mass effect (arrow in B).
Webs tend to occur in the upper thoracic spine.
The reason for the predilection for the upper thoracic spine is unknown.
Treatment is surgical, with possible lysis of web.

中文版：

男性，36歲，慢性後背痛

診斷：Arachnoid Webs

Arachnoid Webs為髓外硬膜下的帶狀蛛網膜組織，可延伸至脊髓表面的軟脊膜，引起脊髓背側局限性凹入性壓跡，稱為「scalpel sign，手術刀徵」（A圖箭頭），並形成佔位效應（B圖箭頭）。
好發於上段胸椎。
好發於上段胸椎的原因不明。
治療方式為手術切除。