The division of the mediastinal space into three compartments is a delineation which serves more than its originally pure anatomic purpose. Tumors arising in each of these spaces bear certain marks of distinction which permit of their general classification according to situation. Thus the anterior mediastinum is the site of election for dermoid and thymoma. The middle mediastinum is the site of bronchogenic carcinoma and lymphosarcoma. From the structures of the posterior mediastinum arise lymphosarcoma and neoplasms such as neurofibroma and ganglioneuroma whose origin may broadly be considered under the term "neurogenic." Neurofibroma is a relatively common tumor; ganglioneuroma, although somewhat of a curiosity, is important from the standpoints of etiology, diagnosis and prognosis. Although Knoebellanch in 1846 reported the first "ganglioneuroma," in the case of "neuroma" reported by Odier in 1803 the lesion undoubtedly was a ganglion cell tumor. It was early recognized that ganglioneuroma can arise from elements