Occult nipple involvement in breast cancer: clinicopathologic findings in 316 consecutive mastectomy specimens.

Purpose: Although breast-conserving surgery is a standard approach for patients with breast cancer, mastectomy often becomes necessary. Surgical options now include nipple-sparing mastectomy but its oncological safety is still controversial. This study evaluates frequency and patterns of occult nipple involvement in a large contemporary cohort of patients with the retroareolar margin as possible indicator of nipple involvement.
Patients and Methods: Three hundred sixteen consecutive mastectomy specimens (232 therapeutic, 84 prophylactic) with grossly unremarkable nipples were evaluated by coronal sections through the entire nipple and subareolar tissue. Extent and location of nipple involvement by carcinoma was assessed with the tissue deep to the skin as potential retroareolar en-face resection margin.
Results: Seventy-one percent of nipples from therapeutic mastectomies showed no pathologic abnormality, 21% had ductal carcinoma in situ (DCIS), invasive carcinoma (IC), or lymphovascular invasion (LVI), and 8% lobular neoplasia (lobular carcinoma in situ). Human epidermal growth factor receptor 2 amplification, tumor size, and tumor-nipple distance were associated with nipple involvement by multivariate analysis (P = .0047, .0126, and .0176); histologic grade of both DCIS (P = .002) and IC (P = .03), LVI (P = .03), and lymph node involvement (P = .02) by univariate analysis. Nipple involvement by IC or DCIS was identified in the retroareolar margin with a sensitivity of 0.8 and a negative predictive value of 0.96. None of the 84 prophylactic mastectomies showed nipple involvement by IC or DCIS.
Conclusion: Nipple-sparing mastectomy may be suitable for selected cases of breast carcinoma with low probability of nipple involvement by carcinoma and prophylactic procedures. A retroareolar en-face margin may be used to test for occult involvement in patients undergoing nipple-sparing mastectomy.