Since first reported by Billroth in 1860, multiple primary carcinoma has been found with relative frequency. No longer can multiple primary malignant growths be considered pathologic curiosities and "remarkably rare."1 The incidence has been estimated at from 0.3 to 4.33 per cent. Warren and Gates2in their statistical survey of recorded cases report an incidence of 3.7 per cent. Hurt and Broders3found 3.34 per cent in 2,124 cases of cancer, while Hellendall4reports an incidence of 4.33 per cent in 685 autopsies. Primary carcinomas may be multiple in one organ or in various structures of the body. They may be synchronous or metachronous: synchronous when of simultaneous occurrence and metachronous when they develop at different times. Criteria have been suggested to establish the independence of multiple growths. Billroth postulated that each neoplasm must show independent histologic characteristics, that each neoplasm must arise from its parent epithelium and that each