The potential for carcinoma existing synchronously on a microscopic level within the second breast.

In the present study, 23 of 314 patients presented with asymptomatic lesions in the second breast, comparing favorably with the incidence of asymptomatic carcinomas of the second breast reported in other series. The type of biopys used appears important, most surgeons advocating resection of a segment of breast ranging from 20 to 30 per cent of the quadrant being sampled. It appears that treatment of carcinoma of the second breast is essentially curative when the lesion is not noted clinically.