Le lesioni mammarie a potenziale neoplastico incerto (B3) diagnosticate su Core Needle Biopsy (CNB): inquadramento clinico, out come e valutazione dell’opzione chirurgica

TITLE: "Uncertain malignant potential breast lesion (B3) diagnosed on core needle biopsy (CNB): clinical presentation, outcome and evaluating surgical option" INTRODUCTION Core needle biopsy (CNB) have been introduced to increase the accuracy of diagnosis of breast cancer and to exclude from surgery benign lesions, with savings of injured tissues. However, a fair percentage of CNB are still classified, according to European guidelines, in the B3 category, which includes a heterogeneous group of lesions with uncertain malignant potential. The aim of this study is to evaluate the positive predictive value (PPV) on excisional biopsies (EB) after the diagnosis of B3 in our experience at Campus Bio-Medico of Rome and compare them with data in the literature to evaluate the possibility of a different treatment for each histological subgroup. MATERIALS AND METHODS: From May 2003 to May 2011 were performed 808 CNB, stereo as well as US guided, at the Breast Unit of the Campus Bio-Medico. One hundred and sixteen of these (14.4%) were classified as B3. Ninety-five patients (81.9%) underwent BE. RESULTS It was confirmed the diagnosis of CNB in 47 cases (49.5%), in 31 (32.6%) definitive histology was of benign lesions, in 14 cases (14.7%) cancer in situ , ductal or lobular, was diagnosed, and in three (3.1%) an invasive cancer was detected. Overall, the PPV is of 17.9%. In particular, all malignant lesions were associated with atypia. Lobular Intraepithelial Neoplasia (LIN) grade 2 and 3 showed, at histological examination of EB, respectively PPV of 54.5% and of 66.7%, while LIN1 of 15.8%. In our series Ductal Intraepithelial Neoplasia (DIN) 1a and b have a PPV of 12.5% and 4%. Aftere the diagnosis of 6 papillary lesions, EB showed foci of carcinoma in situ inone case (PPV 16.7%). Two/8 radial scars, both associated with DIN1, were tumors in situ at the excisional biopsy. Excisional biopsy confirmed the other types of lesions (Phyllodes tumors, Fibroepithelial lesions). DISCUSSION AND CONCLUSIONS The European Guidelines for the Diagnosis of breast cancers define B3 "lesions that may be benign on histology of BE, but it is known that heterogeneity can show, or have an increased risk (although low) to be associated in malignant lesions. " In our series the PPV was 17.9% and is associated in all cases but one (papillary lesions) with ductal or lobular intraepithelial neoplasia (LIN and DIN1-b). At a review of the literature, we believe that with a diagnosis of B3 at the CNB is mandatory a EB if is present LIN2 and 3 and recommended in LIN1 and DINA-b. We also propose that should be sent to EB every atypical papillary lesions and phyllodes tumor, because of the natural history of these tumors. Instead the opportunity of EB in other types of lesions classified B3 should be discussed in multidisciplinary meetings. REFERENCES Bianchi S. “Positive predictive value for malignancy on surgical excision of breast lesions of uncertain malignant potential (B3) diagnosed by stereotactic vacuum-assisted needle core biopsy (VANCB): a large multi-institutional study in Italy” Breast 2011; 20; 264-270 European Commission Working Group on Breast Screening Pathology. Quality assurance guidelines for pathology. Perry N. Ed. Luxemburg: Office for official publications of the European Communities; 2006: 219-312