Unlike arachnoid meningoceles, arachnoid cysts frequently cause local pressure effects probably because there is no free communication between the cyst and the subarachnoid space. Following the first detailed description of cystic lesions of spinal nerve roots by Tarlov in 1938, a simplified classification of spinal meningeal cysts was developed in 1988, containing three major categories. The authors report on a lumbar intraspinal extradural meningocele that caused incomplete paraplegia in an otherwise healthy 31-year-old man in whom magnetic resonance imaging revealed stigmata of Scheuermann disease. Intraoperatively, the lesion was classified as a transitional-type lesion, in accordance with Type IA of the Nabors classification, because a communication with the subarachnoid space was observed. After complete removal of the meningocele, the patient's recovery was prompt and complete.