Pathologic-radiologic correlation in evaluation of retroareolar margin in nipple-sparing mastectomy

Nipple-sparing mastectomy (NSM) has recently been increasing in popularity due to a better cosmetic outcome and quality-of-life benefit. The radiologic distance between the tumor and the nipple is independently predictive of nipple-areolar complex involvement and can assist in patient selection for NSM. However, concordance between the preoperative radiologic imaging and histologic evaluation would play a major role in making patient selection for NSM meaningful. We analyzed the pathologic-radiologic correlation for evaluation of retroareolar (RA) margin in NSM. A retrospective histologic and blinded radiologic review of 80 NSM (41 therapeutic and 39 prophylactic) performed on 45 patients was done. Histologically, the cases were divided into positive or close (invasive or in situ carcinoma within 5 mm of the RA margin) and negative (greater than 5 mm from the RA margin). Radiographically, positive cases were defined as suspicious enhancement and/or suspicious findings within 20 mm of the nipple on magnetic resonance imaging (MRI) and/or diagnostic mammography, respectively. Thirty five of 41 (85.4 %) therapeutic cases were concordant. Six cases were discordant, with 2/41 (4.9 %) discordant cases classified as positive at histology, but negative on imaging and 4/41 (9.75 %) discordant cases classified as negative at histology, but positive on imaging. Agreement between pathology and radiology was moderate [kappa coefficient 0.54 (p = 0.0003)].We conclude that there is a significant agreement between histologic and radiologic evaluation for assessment of RA margin and preoperative radiologic imaging; specifically, MRI provides valuable information and should be strongly recommended to help select patients for NSM.