Fibroepithelial Lesions With Cellular Stroma on Breast Core Needle Biopsy: Are There Predictors of Outcome on Surgical Excision?

Abstract

Fibroepithelial lesions with cellular stroma (FELCS) in breast core needle biopsy (CNB) specimens may result in either fibroadenoma or phyllodes tumor at excision. We evaluated histologic features, proliferation indices (by Ki-67 and topoisomerase II a immunostaining) and p53 expression in 29 cases of FELCS in CNB specimens and correlated these with excision findings in a blinded manner. On excision, 16 patients had fibroadenomas and 12 had phyllodes tumors. All CNB specimens with mildly increased stromal cellularity were fibroadenomas on excision (n=4), and all with markedly cellular stroma were phyllodes tumors (n=4). Among CNB specimens with moderate cellularity (12 fibroadenomas and 8 phyllodes tumors), only stromal mitoses were discriminatory histologically. Stromal proliferation indices were significantly higher in CNB that were phyllodes tumors vs fibroadenomas. Assessment of stromal cellularity, mitoses, and proliferation indices might help determine the probability of phyllodes tumor occurring and guide management of these cases.

486 From the 1 Department of Pathology, Faculty of Medicine, University Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia, 2 Department of Surgery, Faculty of Medicine, University Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia, 3 Department of Anatomy, Faculty of Medicine, University Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia Received: Jan. 18, 2011; Accept: Mar. 8, 2012 Correspondence to: Dr. Siti Aishah Md Ali, Department of Pathology, Faculty of Medicine, University

“…[17,33] Our results showed a significant difference of MIB-1 positivity in stromal components. The expression of MIB-1 in our study in stroma was 15.6%, 35.3% and 21.4% in benign, borderline and malignant PTs, respectively, within the range of an earlier report by Tse et al [32] Published studies showed that Ki-67 and p53 [7,17,19] p53 is useful as independent criteria for evaluating the malignancy of PT and its expression tends to be greater in the PT with a higher malignant potential. [34] In the present study, low levels of expression were significantly found in the epithelium, 2.3% (1/44), 5.9% (1/17), 20% (1/5) of benign PT, borderline PT and malignant PTs, respectively.…”

“…[7,21] Previous studies and our study have shown a correlation between MIB-1 positivity and the histological grades. [7,19,32] MIB-1 negativity or low expression indicated a very low proliferation rate, apparently noticeable in FA and benign PT. MIB-1 positivity in more than 10% of cells within a benign PT has been used as a risk for malignant change.…”

“…[6] Expression of the proliferation marker Ki-67 has been reported to vary among histological categories of PT as well as between PTs and FAs and was also reported in several studies to show a correlation between MIB-1 positivity and the histological grade. [7,19,20] Besides, p53 immunohistochemical expression, commonly used as an identification for tumor-suppressor gene mutation, has been also correlated with tumor grade. [7,21] It is located on the short arm of chromosome 17p13, is a wellknown tumor suppressor gene, plays a role in the regulation of normal cell growth and division, DNA repair and apoptosis.…”

Phyllodes Tumor of the Breast: Analysis of 48 Patients

“…Additionally, false-negative results can be obtained from FNAC when sampling is performed in an area of hypocellular stroma. PT can be histologically distinguished from FA by nuclear atypia, increased stromal cellularity, mitotic activity, and ratio of stroma to epithelium (20). Core needle biopsy is considered more reliable than FNAC in obtaining a correct diagnosis because it can provide specific histopathologic findings.…”

Fibroepithelial Tumors of the Breast: Pathologic and Immunohistochemical Features and Molecular Mechanisms

“…Although CNB can provide high negative and positive predictive values, accurate diagnosis based on a limited sample from CNBs can sometimes be challenging for fibroepithelial neoplasms because of the heterogeneity and overlapping features in these lesions. 9,10,26 At times, fibroadenoma can show moderate cellularity, mimicking PTs, and PTs may have heterogeneous components similar to benign fibroadenoma. Many studies have shown the need for biomarkers, especially Ki-67, in addition to the histologic features of these lesions for more accurate preoperative evaluation.…”