Benign neoplasms arising from the medulla of the adrenal gland or of similar structure but occurring outside the gland in the retroperitoneal space are being reported with increasing frequency. In 1934 Belt and Powell1reviewed thirty-six reported cases, and by 1939 one of us (E. H.) was able to collect 103 cases in the literature. Most of the reports deal with postmortem observations. In 1922 Labbé, Tinel and Doumer2first described the clinical syndrome caused by these growths. In 1926 Vaquez, Donzelot and Geraudel3were the first to make a clinical diagnosis of such a neoplasm and advise operation. The patient refused this and the diagnosis was confirmed later at necropsy.4Charles Mayo5was the first to remove successfully such a neoplasm causing the typical syndrome, but at the moment the true nature of the tumor was not appreciated. The case reported by Pincoffs and