Large intradural craniospinal arachnoid cyst: A case report and review of literature
A 39-year-old male presented with 8-month history of progressively increasing neck pain and headache. To start with, the headache was suboccipital, which gradually became holocranial. He also complained of worsening vomiting over previous 3 months. For the past 20 days, he had developed numbness of face, diminution of vision in both eyes, and diminished taste sensation in the anterior part of tongue. No other complaint was reported. There was no past history of trauma to the craniospinal region.\nOn neurological examination, visual acuity was found to be 6/36 bilaterally, with fundus showing papilledema. There was diminution of corneal reflex, with decreased sensation over V1, V2, and V3 divisions. Taste sensation from anterior two-thirds of the tongue was diminished. No other neurological abnormality was found. All routine laboratory investigations were within normal range. No congenital malformations were present.\nPlain X-ray of the cervical spine was normal. Computed tomographic (CT) scan of head showed a well-circumscribed extra-axial midline hypodense lesion in the posterior fossa []. Magnetic resonance imaging (MRI) brain revealed posterior fossa midline extra-axial well-marginated T1WI hypointense, T2WI hyperintense non-enhancing cystic lesion with elliptical elongation below the foramen magnum [Figure , , and ]. There was associated mass effect compressing the 4th ventricle, causing non-communicating hydrocephalus []. MRI of craniospinal axis revealed the same cystic lesion extending down through foramen magnum up to the lower border of C5 vertebra, communicating with the spinal subarachnoid space, compressing and displacing the medulla oblongata and proximal cervical cord [].\nThe patient underwent posterior decompression through C5 laminectomy. Upon opening the dura, a bluish thin-walled cyst was encountered dorsal to the spinal cord. Clear fluid was aspirated from the cyst and a partial excision of the cyst wall was carried out. Histopathologic examination of the cyst wall confirmed it to be an arachnoid cyst []. The patient rapidly improved following the surgery. CT scan done on 8th postoperative day revealed decreased size of the lesion []. He made a full recovery and was asymptomatic at 6-month follow-up examination.