Abstract Introduction: The analyses of sub nipple tissue (SNT) have been used by some surgeons to preserve or not the nipple in nipple sparing mastectomy for breast carcinoma. Therefore, the intraoperative study of SNT becomes an important tool. However, it is uncertain if the SNT evaluation can safely predict the nipple involvement for carcinoma. The aim of this study was to evaluate the accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of intraoperative imprint cytology, intraoperative frozen section and postoperative paraffin histopathology of SNT to predict involvement of the nipple in women with breast carcinoma. Methods: It was realized a prospective study with 38 consecutives breast carcinoma women (stage 0, I, II and III) underwent to mastectomy. It was excluded inflammatory carcinoma and clinical evident nipple involvement. After mastectomy, the nipple areolar complex were dissected in an approximate thickness of 5mm simulating nipple-sparing flap dissection. Then, the SNT were dissected and submitted to imprint citology and frozen section during intraoperative time. Subsequently, it were submitted to routine paraffin histopathology analysis. The nipple was examined separately by paraffin histopathology (considered the gold standard). We considered any atypical cells like positive findings in all exams (cytology, frozen and paraffin). Results: The mean of patient’s age was 59 years, the mean of tumor size was 34 mm in clinical exam and 31mm in pathological exam. The clinical and mammographic means of distance from tumor to nipple were 23 and 34 mm, respectively. The imprint citology frozen section and paraffin histopathology of SNT showed: sensitivity 42.9%, 42.9% and 57.1%; specificity 80.6%, 96.8% and 100%; accuracy 73.7%, 86.8% and 92.1%; PPV 33.3%, 75% and 100%; NPV 86.2%, 88.2% and 91.2%, respectively. When we associated both intraoperative exams (imprint cytology and frozen section), the specificity (80.6% x 100%, p=0.01) and accuracy (76.3% x 92.1%, p=0.02) were worse than postoperative exam. The false negative of postoperative analyses was 8.8%. Conclusion: These preliminaries outcomes showed a moderate sensitivity and good specificity of three exams, the low false negative rate of postoperative paraffin exam. Our dates suggest that SNT evaluation is a good method to predict nipple involvement and possibly the postoperative evaluation (histopathology) is better than intraoperative evaluation (imprint cytology and frozen section). Citation Format: Giuliano M Duarte, Maria Virginia Thomazin, André Oliveira, Fernado Tocchet, Luciana Moreira, Adriana Worschech, Renato Z Torresan. Cytology and histopathology evaluation of sub-nipple tissue during intraoperative and postoperative time to predict neoplastic involvement of the nipple in patients with breast carcinoma [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-13-25.