Introduction/Background Extemporaneous examination is a pathological examination performed as soon as the specimen is taken, not fixed, during a surgical procedure, in order to rapidly provide the surgeon with a diagnosis likely to modify the course of the surgical procedure.

The objective of our study was to test the reliability of the extemporaneous examination in mammary pathology, to compare our results with those of the literature and to raise the main diagnostic problems with regard to extemporaneous examination (false positives, false negatives).

Methodology We realised a retrospective study of 80 patients with breast cancer in the Mohammed VI Center for the Treatment of Cancers of the CHN IBN ROCHD of Casablanca during the year 2017.

Results Reliability of extemporaneous examination in breast cancer was assessed by its performance indices: sensitivity (Ss), specificity (Sp), positive predictive value (VPP) and negative predictive value (VPN).

In our series, the sensitivity was 98% and the VPP was 100%, which matches the results reported in the series of experts, for the specificity and the VPN we could not calculate them since we did not have the ‘true negative’ variant.

Conclusion In conclusion, EE is very sensitive in breast pathology and it meets its objectives, namely to ensure the diagnosis of malignancy in the breast without false positive.

Disclosure Nothing to disclose.