PMC7509563_01
Sagittal MRI and CT myelography demonstrate a dorsal indentation, the so-called "scalpel sign," at the T4 level.
CRIOR2020-8816598.001.jpg
PMC7509563_01_CRIOR2020-8816598.001.jpg
fig1
T4 level was seen on MRI. T2-weighted sagittal MRI demonstrated a sharp dorsal indentation of the spinal cord (Figures 1(a) and 1(c)). CT myelography showed the same changes of the spinal cord as MRI (Figures 1(b) and 1(d)).
(a) Intraoperative findings show a membrane-like structure in the subarachnoid space. (b) Fibrous tissue seen on hematoxylin and eosin staining. (c) Epithelial membrane antigen-positive epithelial tissue is seen. (d) Calcification seen on hematoxylin and eosin staining (arrow). (e, f) On postoperative MRI, the spinal cord deviation and scalpel sign have disappeared.
CRIOR2020-8816598.002.jpg
PMC7509563_01_CRIOR2020-8816598.002.jpg
fig2
The arachnoid membrane was then resected (Figure 2(a)). No inflammatory cells or neoplastic lesions were detected (Figures 2(b)-2(d)). His postoperative MRI showed that the scalpel sign had disappeared, and the spinal cord was shifted posteriorly (Figures 2(e) and 2(f)).
PMC7509563_02
Preoperative T2-weighted MRI and CT myelography. (a, b) Sagittal MRI and CT myelography show the "scalpel sign." The white line indicates the T5/T6 disc level. (c, d) Axial MRI and CT myelography show spinal cord deviation.
CRIOR2020-8816598.003.jpg
PMC7509563_02_CRIOR2020-8816598.003.jpg
fig3
T2-weighted sagittal MRI demonstrated a sharp dorsal indentation of the spinal cord (Figures 3(a) and 3(c)), and CT myelography showed the same change of the spinal cord (Figures 3(b) and 3(d)).
(a) The right side is cranial, and the left side is caudal. The dura and arachnoid are incised. The arachnoid web is still present as a restiform structure (black arrow). (b) After resection of the arachnoid web. (c) Hematoxylin and eosin staining shows fibrous tissue and microcalcifications. (d) Elastica-Masson staining shows epithelial tissue. (e, f) Postoperative sagittal and axial CT myelography show no spinal cord deviation, and the "scalpel sign" has vanished. The white line shows the T5/T6 disc level.
CRIOR2020-8816598.004.jpg
PMC7509563_02_CRIOR2020-8816598.004.jpg
fig4
The arachnoid membrane was then resected (Figures 4(a) and 4(b)). No inflammatory cells or neoplastic lesions were detected (Figures 4(c) and 4(d)). The scalpel sign on MRI seen before surgery has vanished (Figures 4(e) and 4(f)).