A 67-year-old woman with neurofibromatosis type 1 presented with progressive dyspnea. Radiologic evaluation and magnetic resonance imaging revealed progression of a giant meningocele associated with hydrothorax. Laminoplasty with incision of the meningocele and dural plasty was performed, although nerve rootlets were killed. Microsurgical incision of the neck of the meningocele is a favorable operation even in large meningoceles such as the present case.