Percutaneous core biopsy (CB) has been introduced to increase the ability of accurately diagnosing breast malignancies without the need of resorting to surgery. Compared to conventional automated 14 gauge needle core biopsy (NCB), vacuum-assisted needle core biopsy (VANCB) allows obtaining larger specimens and has recognized advantages particularly when the radiological pattern is represented by microcalcifications. Regardless of technical improvements, a small percentage of percutaneous CBs performed to detect breast lesions are still classified, according to European and UK guidelines, in the borderline B3 category, including a group of heterogeneous lesions with uncertain malignant potential. We aimed to assess the prevalence and positive predictive values (PPV) on surgical excision (SE) of B3 category (overall and by sub-categories) in a large series of non-palpable breast lesions assessed through VANCB, also comparison with published data on CB. Overall, 26,165 consecutive stereotactic VANCB were identified in 22 Italian centres: 3107 (11.9%) were classified as B3, of which 1644 (54.2%) proceeded to SE to establish a definitive histological diagnosis of breast pathology. Due to a high proportion of microcalcifications as main radiological pattern, the overall PPV was 21.2% (range 10.6%-27.3% for different B3 subtypes), somewhat lower than the average value (24.5%) from published studies (range 9.9%-35.1%). Our study, to date the largest series of B3 with definitive histological assessment on SE, suggests that B3 lesions should be referred for SE even if VANCB is more accurate than NCB in the diagnostic process of non-palpable, sonographically invisible breast lesions.

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One of the most controversial issues in breast pathology is whether lobular neoplasia (LN) is a risk factor or a precursor lesion of invasive lobular carcinoma (ILC). This is consequent to the fact that no conclusive data on the biology of LN exist. Molecular studies of LN and ILC are scanty, variable, and not consistent. Clonality of 12 cases of LN and ILC present simultaneously in the same block has been studied. Cells from both lesions were obtained by microdissection and were studied for mitochondrial DNA (mtDNA), D-loop sequencing, and neighbor-joining trees. Eight of the same cases were studied with comparative genomic hybridization (CGH) array to have additional data consistent with mtDNA. In all cases, loss of heterozygosity was studied for D16S496,locus 16q22.1 related to e-cadherin. It appears that no fewer than eight cases were genetically very similar (clonal) with mtDNA. Seven of these cases appeared also clonal with CGH array. It is concluded that in the present series, LN and ILC are genetically related lesions in the majority of cases and that LN might be the precursor of ILC.

Flat epithelial atypia (FEA) may represent the earliest precursor of low-grade breast cancer and often coexists with more advanced atypical proliferative breast lesions such as atypical ductal hyperplasia (ADH) and lobular intraepithelial neoplasia (LIN). The present study aims to investigate the association between morphological parameters of FEA and presence of malignancy at surgical excision (SE) and the clinical significance of the association of FEA stereotactic 11-gauge vacuum-assisted needle core biopsy (VANCB), reporting a diagnosis of FEA, ADH or LIN with subsequent SE from 14 pathology departments in Italy. Available slides were reviewed, with 114 (19.4 %) showing a malignant outcome at SE. Among the 190 cases of pure FEA, no statistically significant association emerged between clinical-pathological parameters of FEA and risk of malignancy. Logistic regression analyses showed an increased risk of malignancy according to the extension of ADH among the 275 cases of FEA associated with ADH (p00.004) and among the 34 cases of FEA associated with ADH and LIN (p00.02). In the whole series, a statistically significant increased malignancy risk emerged according to mammographic R1-R3/R4-R5 categories (OR01.56; p0 0.04), extension (OR01.24; p00.04) and grade (OR01.94; p00.004) of cytological atypia of FEA. The presence of ADH was associated with an increased malignancy risk (OR02.85; p<0.0001). Our data confirm the frequent association of FEA with ADH and/or LIN. A diagnosis of pure FEA on VANCB carries a 9.5 % risk of concurrent malignancy and thus warrants follow-up excision because none of the clinical-pathological parameters predicts which cases will present carcinoma on SE.

Malignant rhabdoid tumours (MRTs) are highly aggressive neoplasms which most frequently occur in the kidney of young children. Several cases of primary MRT occurring in extra-renal sites have been reported, particularly in the soft tissues. We report a case of primary MRT of the uterus, a very rare site for this neoplasm, with morphological, immunohistochemical and ultrastructural features corresponding to restrictive morphological criteria for MRT. The possible differential diagnoses were considered.