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Case 9

History:

29 year old female with chronic mid back pain and paresthesia

Findings:

Axial and sagittal T2 WI showing the presence of a cystic lesion in the upper thoracic region resulting in mass effect and anterior displacement of the spinal cord with loss of CSF–cord interface.

Diagnosis:

Spinal Arachnoid Cyst

Discussion:

Spinal arachnoid cysts are relatively uncommon lesions that may be intradural or extradural with the extradural being more frequent. The vast majority occur in the thoracic region with only 15% in the cervical region and 5% in the lumbar region.   Most are dorsal to the spinal cord (80%). Acquired intradural cysts may be anterior, posterior or lateral to the spinal cord. Such secondary arachnoid cysts are believed to arise from arachnoiditis.

MRI is the imaging modality of choice. The differential diagnosis on imaging includes other intradural cystic lesions like dermoids, epidermoids, hydatidosis and cysticercosis. Spinal cord herniation may show anterior displacement of the cord but without discrete cystic lesions.

References:

  • Van Paesschen W, Van Den Kerchove M, Appel B, Klaes R, Neetens I, Lowenthal A. Arachnoiditis ossificans with arachnoid cyst after cranial tuberculous meningitis. Neurology 1990;40:714–6.
  • Lee H-J, Cho D-Y. Symptomatic spinal intradural arachnoid cysts in the pediatric age group: description of three new cases and review of the literature. Pediat Neurosurg 2001;35:181–7.
  • Osborn AG. Tumours, cysts, and tumour like lesions of the spine and spinal cord. diagnostic neuroradiology. St Louis, MO: Mosby Year Book, Inc., 1994:876–918.
  • Kazan S, Ozdemir O, Akyuz M, Tuncer R. Spinal intradural arachnoid cysts located anterior to cervical spinal cord: report of two cases and review of literature. J Neurosurg (Spine 2) 1999;91:211–5.
  • Agnoli AL, Schonmayr R, Laun A. Intraspinal arachnoid cyst. Acta Neurochir (Wein) 1982;61:291–302.