The usual location of intrathoracic neurogenic tumors is the posterior mediastinum. Those in a mediastinal anterior or middle location arise from the intrathoracic phrenic nerve, which is extremely rare and causes a problem for etiologic diagnosis. We report what is, to our knowledge, the second case of a mediastinal neurofibroma originating from the phrenic nerve of a 59-year-old woman without von Recklinghausen disease. Diagnosis was suggested by the radiologic features and confirmed by histologic aspects after excision. The prognosis after complete resection is excellent. © 2011 The Society of Thoracic Surgeons