Correlations of morphological features and surgical management with clinical outcome in a multicentre study of 241 phyllodes tumours of the breast

Stromal Ki67 Expression Might be a Useful Marker for Distinguishing Fibroadenoma From Benign Phyllodes Tumor of the Breast

Background. Fibroadenoma (FA) and benign phyllodes tumor (PT) of the breast often have similar appearances on imaging. While an exact diagnosis of biopsy specimens is required to choose adequate treatment, including surgical procedures, it is sometimes difficult to pathologically differentiate these 2 tumors due to histological resemblances. To elucidate markers for distinguishing FA from benign PT, we analyzed clinical samples immunohistochemically. Methods. We retrospectively investigated 80 breast fibroepithelial lesions. As a discovery set, 60 surgical excision samples (30 FA and 30 benign PT) were examined. Twenty biopsy samples (10 FA and 10 benign PT) were examined as a validation set. To determine targets for immunohistochemistry, we first tested some proteins based on previous reports. As a result, Ki67 was chosen for differentiating FA and PT; thus further examinations were conducted with this protein. Results. Among the proteins examined, stromal Ki67 was significantly higher in PT than in FA. Benign PT had significantly higher stromal Ki67 expression both at random and at hotspots (p < .001 and <.001, respectively). The receiver operating characteristic curve analysis identified 3.5% and 8.5% (at random spots and hotspots, respectively) as the optimal cutoff values of stromal Ki67 for distinguishing between these 2 tumors. In the validation cohort employing needle biopsy specimens, we confirmed that these 2 cutoff values properly classified these 2 tumors (p = .043 and .029, respectively). Conclusion.We revealed that stromal Ki67 might be a potential marker for distinguishing FA from benign PT.

Recurrence is Not Associated with Margin Status in Phyllodes Tumor

BACKGROUND

Phyllodes tumor (PT) is a rare fibroepithelial neoplasm of the breast. The proper extent of resection is still under debate. This study aimed to investigate the optimal surgical margin to prevent recurrence after surgery for PT and to evaluate risk factors for local recurrence (LR).

METHODS

Retrospective analysis of a prospective cohort database was performed. Patients who underwent curative surgery for PT at Seoul National University Bundang Hospital between July 2003 and February 2022 were reviewed.

RESULTS

Of the 439 patients included, 285 were benign, 129 were borderline, and 25 were malignant. There was no statistically significant difference in 5-year disease-free survival (DFS) between margin-negative and margin-involved patients (87.3% vs. 85.1%, p = 0.081). When patients were classified into groups, according to margin status, as conventional (≥ 1 cm from tumor), close (< 1 cm from tumor), or involved, 5-year DFS rates were also similar (100% vs. 86.9% vs. 85.1%, p = 0.170). In subgroup analysis for different histologic grades, 5-year DFS was not affected by margin involvement. In univariate analysis, large tumor size (> 5 cm; hazard ratio [HR] 2.857, p = 0.028) and infiltrative tumor border (HR 3.096, p = 0.012) were independent risk factors for LR. Further multivariate analysis found both factors to be prognostic.

CONCLUSIONS

Recurrence was not significantly influenced by margin status in all histological grades. In benign and borderline tumors, local excision without wide surgical margins could be sufficient, and watchful waiting could be an option for patients with positive margins after initial surgery.

Survey of recurrent diagnostic challenges in breast phyllodes tumours

BACKGROUND

Breast phyllodes tumours (PTs) are graded as benign, borderline, or malignant by analysis of multiple histological features. PT grading is often inconsistent, likely due to variation in the weighting of grading criteria by pathologists.

DESIGN

The hierarchy of use of diagnostic criteria was identified using a 20-question survey.

RESULTS

In all, 213 pathologists from 29 countries responded. 54% reported 10-50 PT cases per year. Criteria considered key to PT diagnosis were: increased stromal cellularity (84.3%), stromal overgrowth (76.6%), increased stromal mitoses (67.8%), stromal atypia (61.5%), stromal fronding (59.0%), periductal stromal condensation (58.0%), irregular tumour borders (46.3%), and/or lesional heterogeneity (33.7%). The importance of grading parameters were: mitotic activity (55.5%), stromal overgrowth (54.0%), stromal atypia (51.9%), increased stromal cellularity (41.7%), and nature of the tumour border (38.9%). 49% would diagnose malignant PT without a full array of adverse features. 89% used the term "cellular fibroepithelial lesion (FEL)" for difficult cases; 45% would diagnose an FEL with stromal fronding (but lacking other PT features) as fibroadenoma (FA), 35% FEL, and 17% PT. 59% deemed clinico-radiological findings diagnostically significant; 68% considered age (≥40 years) important in determining if an FEL was a FA or PT. In FELs from young patients, increased stromal cellularity (83%), fronding (52%), and mitoses (41%) were more common. 34% regarded differentiating cellular FA from PT as a specific challenge; 54% had issues assigning a borderline PT grade.

CONCLUSION

Criteria for grading PT lie on a spectrum, leading to interpretive variability. The survey highlights the criteria most used by pathologists, which do not completely align with WHO recommendations.

CD117/c-KIT Expression in Phyllodes Tumor of the Breast and Its Correlation With Morphology and Clinical Outcome

Introduction

Breast phyllodes tumor’s (PT) clinical behavior is difficult to predict on histology. There is limited amount of data available on the role of biological markers. The objective of this study was to assess the expression of CD117 (c-KIT) in PT of the breast and its relationship with morphology and clinical outcome.

Methods

A total of 78 patients having available clinical records between 2004 and 2014 with breast PT were retrieved from the cancer registry at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore and were followed up. Immunohistochemical studies were performed on all the cases using mono­clonal antibody CD117 (DAKO A4502) using Leica Bond-Max automated biosystem (Leica Biosystems, Melbourne, Australia). Staining proportion and intensity of both epithelial and stromal elements were analyzed. Evaluation of the protein expression was determined and scored.

Results

Patients’ mean age was 45.13 ± 11.4 years. Thirty-nine (50.0%) patients had tumor on right side, 38 (48.7%) had on left and only one (1.3%) was bilateral. Thirty-two (41.0%) patients had benign PT, 21 (26.9%) had borderline and 25 (32.1%) had malignant PT. Negative CD117 expression was observed in 20 (62.5%), eight (38.0%) and 12 (48.0%) of benign, borderline and malignant PTs, respectively. Positive CD117 expression was observed in 12 (37.5%) benign, 13 (61.9%) borderline and 13 (52.0%) malignant PTs. There was insignificant association between CD117 expression with respect to tumor sub-type, patient’s age and clinical behavior (p-value > 0.05).

Conclusion

CD117 expression was not found to be associated with tumor type and was not associated with increased risk of recurrence in this sample of patients. Further work is needed to better understand the prognostic value of CD117 expression in breast PTs.