Neoplastic involvement of nipple and skin flap in carcinoma of the breast.

This study was carried out to determine the frequency of neoplastic involvement of the nipple and of the skin flap in 1,000 mastectomy specimens with primary breast carcinomas. Nipple involvement (Paget's, and carcinoma in ducts or stroma or in lymphatics) was encountered in 23.4% of the cases and appeared to be more frequently associated with tumors of large size or located in the central sector of the breast, and with the intraductal and small cell carcinomas. The skin flap was invaded by the underlying tumor in 101 cases, particularly when the tumors were over 2 cm in diameter and when the nipples were involved. In 12 additional cases, tumor emboli in dermal lymphatics were discovered microscopically in random sections of the skin flap. The neoplastic involvement could not be recognized grossly in 58% of the involved nipples, in 28.7% of the skin flaps directly invaded by an underlying tumor, and in nine of the 10 cases with microscopic emboli dermal lymphatics and in which the gross appearance of the skin was recorded. A high incidence of axillary metastases was found in association with nipple and skin involvement.