A 26-year-old female presented with a lateral thoracic meningocele associated with neurofibromatosis. The development of the thoracic meningocele was documented on serial chest roentgenograms. Magnetic resonance imaging and three-dimensional bone computed tomography scans were particularly useful to identify organic changes in the surrounding structures and the osseous orifice of the dural sac, respectively. The large thoracic meningocele was successfully treated through the posterolateral extradural approach in combination with resection of the adjacent ribs and cerebrospinal fluid drainage from the dural sac.