Role of Ki67 Expression in Distinguishing Benign and Malignant Phyllodes Tumors of the Breast: A Prospective Observational Study.
DOI:
https://doi.org/10.51168/c82k2356Keywords:
Phyllodes tumor, Ki67, Breast neoplasm, Immunohistochemistry, Stromal proliferation, Malignant phyllodes tumorAbstract
Background:
Phyllodes tumors (PTs) are rare fibroepithelial neoplasms of the breast with biological behavior ranging from benign to malignant. Histopathological grading may be challenging because of overlapping morphological features. Ki-67 is a marker of cellular proliferation that may provide additional information regarding tumor aggressiveness.
Objective:
To evaluate the association between stromal Ki67 expression and histological grade of phyllodes tumors and determine its relationship with tumor size and age.
Methods:
A prospective observational study was conducted in the Department of General Surgery, Indira Gandhi Institute of Medical Sciences (IGIMS), Patna. Twenty patients with histopathologically confirmed phyllodes tumors were evaluated. Clinical, radiological, histopathological, and immunohistochemical assessments were performed. Stromal Ki67 labeling index (LI) was calculated and analyzed in relation to histological grade, tumor size, and age. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic performance of Ki67 for identifying malignant tumors.
Results:
Of 20 patients, 11 (55%) had benign, 4 (20%) borderline, and 5 (25%) malignant tumors. Mean Ki67 LI increased significantly across the three groups: 6.1 ± 2.4% in benign, 16.8 ± 3.9% in borderline, and 31.4 ± 6.2% in malignant tumors (ANOVA F=48.71, p<0.001). Tumor size was significantly associated with histological grade (p=0.002) and positively correlated with Ki67 expression (r=0.68, p=0.001). A Ki67 cutoff of ≥20% showed a sensitivity of 88.9%, specificity of 93.3%, and AUC of 0.92 for identifying malignant tumors.
Conclusion:
Stromal Ki67 expression was significantly associated with histological grade and tumor size in phyllodes tumors. Ki67 may serve as an adjunctive marker in distinguishing malignant tumors, although validation in larger studies is required.
Recommendations:
Larger multicenter studies with standardized Ki67 assessment and longer follow-up are recommended to validate the optimal cutoff and clinical utility of Ki67 in phyllodes tumors.
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Copyright (c) 2026 Dr. Prem Prakash, Dr. Rajeev Ranjan, Dr. Anunay Kumar, Dr. Nadeem Ahmed, Dr. Kanchan Sone Lal Baitha, Dr. Rinku Kumari
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