Partial obstruction of the superior vena cava is not uncommon. On the other hand, complete obliteration either by compression or by thrombosis is unusual, and obliteration due to carcinoma is extremely rare.1 I shall therefore in this communication note the instances reported in the literature, describe this condition and add thereto a case observed in Mount Zion Hospital. CASES RECORDED IN THE LITERATURE The first case of obstruction of the superior vena cava was noted in 1806, by Corvisart. At intervals since then cases have been reported and collected as follows: Oulmont,2 1856; Fischer,3 1904; Rauth,4 1911, and Dana,5 1922. Dana, after a critical review of all previously tabulated cases, accepted reports of interference with the circulation in the superior vena cava by "primary carcinoma" of the lung in twenty-three instances, only six of which were verified as carcinoma, and by carcinoma primary in the