The present case reports a 13-year-old patient with an intradural arachnoid cyst, which manifested itself with a sudden loss of strength and sensitivity in the lower and upper limbs and a severe pain in the cervical and thoracic region. On examination, a lesion displayed as an intradural hematoma; however, a laminotomy was performed and it was realized that the lesion was an arachnoid spinal cyst of the cervical-dorsal spine.