Spinal intramedullary arachnoid cyst in a 4-year-old girl: a rare cause of treatable acute quadriparesis: case report.

The authors report their experience in successfully treating a 4-year-old girl who presented with sudden onset of quadriparesis that lasted for 20 days. Magnetic resonance (MR) imaging of the spine revealed an intramedullary cystic lesion extending from C-4 to C-6. A C4-6 laminectomy was performed followed by a median myelotomy. The cyst was decompressed and most of the cyst wall was excised. The histopathological findings were consistent with those of an arachnoid cyst. By postoperative Day 3, power had gradually returned to normal in all her limbs. On follow-up reviews at 2 and 17 months, the results of her neurological examinations remained normal. Follow-up MR imaging of the spine at 17 months revealed an intramedullary residual cystic lesion extending from C-5 to C-6, without any mass effect. An intramedullary arachnoid cyst should be considered in the differential diagnosis of an intramedullary cystic lesion.