PMC6213804_01
Axial T2-weighted image showing the hyperplastic epidural fat compressing the dural sac at the L2-3 (a) and L3-4 (b) levels (arrow). (c) A sagittal image showing anterior displacement of the dural sac because of compression of the hyperplastic epidural fat (arrow)
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F1
T2-weighted images showed degenerative disc disease and hyperplastic epidural fat contributing to L2-3 and L3-4 stenosis [Figure 1a and b]. The sagittal MR studies also revealed anterior displacement of the dural sac due to posterior epidural fat [Figure 1c]. The axial T2-weighted image showed that a hyperintense mass occupied the left side of the spinal canal, and compressed the dural sac at the L4-5 level [Figure 2].
Axial T2-weighted image showing a hyperintense mass occupying the left side of the spinal canal and compressing the dural sac at the L4-5 level (arrow)
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F2
The sagittal MR studies also revealed anterior displacement of the dural sac due to posterior epidural fat [Figure 1c]. The axial T2-weighted image showed that a hyperintense mass occupied the left side of the spinal canal, and compressed the dural sac at the L4-5 level [Figure 2].
(a) Fenestration at the L4-5 level was performed; a yellow, lobulated lipomatous mass (white arrow), and epidural fat (black arrow) were observed in the epidural space. (b) The mass (white arrow) was easily separated from epidural fat (black arrow). (c) Because the mass was enclosed by a fibrous capsule, we could resect it en bloc
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F3
At L4-5, a yellow, encapsulated, lobulated lipomatous mass with epidural fat filled the epidural space [Figure 3a and b]. The lesion was readily dissected away from the dura allowing for an en bloc resection [Figure 3c].
(a) The hyperplastic epidural fat in the epidural space at the L3-4 level. (b) Resection of the hyperplastic epidural fat by piecemeal technique due to the absence of a fibrous capsule
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F4
At the L2-3 and 3-4 levels, additional hyperplastic epidural fat was removed in a piecemeal fashion [Figure 4a and b].
(a) Microscopic findings of the lipoma showing mature adipose tissue enclosed by fibrous tissue [hematoxylin and eosin staining (H and E), x100]. (b) Microscopic findings of epidural fat showing mature adipose tissue without surrounding fibrous tissue (H and E, x100)
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F5
The histological examination of the encapsulated mass showed lobulated mature adipose tissue enclosed by fibrous tissue, compatible with a lipoma, while the histology of the L2-3 and L3-4 epidural fat was consistent with just mature adipose tissue; none of the slides demonstrated cellular atypia [Figure 5a and b].