J Korean Neurosurg Soc.  2012 Sep;52(3):257-260.

Retroperitoneal Spinal Extradural Arachnoid Cyst Combined with Congenital Hemivertebrae

• Park SH
• Kuh SU
• Lim BJ

Abstract

Spinal extradural arachnoid cysts usually cause symptoms related to spinal cord or nerve root compression. Here, we report an atypical presentation of a spinal extradural arachnoid cyst combined with congenital hemivertebra which was presented as a retroperitoneal mass that exerted mass effects to the abdominal organs. On image studies, the communication between the cystic pedicle and the spinal arachnoid space was indistinct. Based on our experience and the literature of the pathogenesis, we planned anterior approach for removal of the arachnoid cyst in order to focus on mass removal rather than ligation of the fistulous channel. In our estimation this was feasible considering radiologic findings and also essential for the symptom relief. The cyst was totally removed with the clogged 'thecal sac-side' end of the cystic pedicle. The patient was free of abdominal discomfort by one month after the surgery.

Keyword

Abdominal discomfort; Cystic pedicle ligation; Extradural arachnoid cyst; Retroperitoneal mass

MeSH Terms

Arachnoid
Arachnoid Cysts
Humans
Ligation
Radiculopathy
Spinal Cord

Figure

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  Fig. 1 Lumbar radiographs. A : Antero-posterior view showing L4 hemivertebra. B : Lateral view showing mild spondylolisthesis L4 on L5.

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  Fig. 2 Magnestic resonance myelography. A : Three dimensional view showing large cystic mass with a pedicle to the spinal thecal sac. B : Coronal view showing the end of cystic pedicle which is clogged.

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  Fig. 3 T2-weighted magnetic resonance images. A : Sagittal view, images are in medial-to-lateral order. B : Axial view, images are in foot-to-head order going clockwise from the left upper image. Note the 'cone-shaped' cystic pedicle.

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  Fig. 4 Intraoperative view. A : Right kidney (white asterisk) and the arachnoid cyst (black asterisk) were exposed after the peritoneum (white arrow head) was retracted. B : Exposure of the arachnoid cyst after further retraction of right kidney. C : The arachnoid cyst was removed and the blunt dissector indicated the origin of the arachnoid cyst.

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  Fig. 5 The specimen. Note that the 'thecal sac-side' end was clogged.

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  Fig. 6 Histopathological examination reveals a cyst composed of thickened arachnoid membrane with attenuated epithelial cells (Hematoxylin and Eosin, A : ×40, B : ×100, respectively).

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  Fig. 7 Postoperative T2-weighted magnetic resonance images. Sagittal view, axial view and coronal view showing no residual cyst.

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