Tumor Budding and Tumor-Infiltrating Lymphocytes in Invasive Breast Carcinoma: A Single-Centre Observational Histopathological Stud

Background Tumor budding reflects detachment of single malignant cells or small cell clusters from the main tumor and is increasingly recognized as a morphologic indicator of invasive potential. Tumor-infiltrating lymphocytes represent the host immune response within the tumor microenvironment and provide complementary biological information in breast carcinoma. Objectives To assess intratumoral budding, peritumoral budding, stromal tumor-infiltrating lymphocytes, and intratumoral tumor-infiltrating lymphocytes in invasive breast carcinoma and determine their associations with selected clinicopathological parameters. Methods This hospital-based observational histopathological study included 42 mastectomy specimens. Hematoxylin and eosin-stained sections were examined for tumor-budding hotspots. Intratumoral and peritumoral budding were categorized as high or low using the study-defined threshold of more than four buds across 10 high-power fields. Tumor-infiltrating lymphocytes were assessed morphologically and analyzed using the recorded low and high categories. Estrogen receptor, progesterone receptor, and HER2 results were available for a subset of cases. Associations were assessed using chi-square testing, with statistical significance set at p<0.05. Results High ITB and PTB were each identified in 19/42 cases (45.2%). Both ITB (p=0.0001) and PTB (p=0.0006) showed statistically significant associations with lymph-node metastasis, which was present in 19/42 cases (45.2%). Low iTILs were observed in 34/42 cases (81.0%), while low sTILs were identified in 29/42 cases (69.0%). PTB showed no significant association with iTILs (χ²=0.0905; p=0.763) or sTILs (χ²=0.5631; p=0.453). Associations of tumor budding with age, lymphovascular invasion, histological grade, tumor size, and receptor status were not statistically significant (all p>0.05). Conclusion Tumor budding, particularly its association with nodal metastasis, appears to identify an aggressive histomorphological phenotype in invasive breast carcinoma. The present series did not demonstrate a significant relationship between tumor budding and tumor-infiltrating lymphocyte categories. Recommendations Larger multicentre studies using standardized budding and lymphocyte-scoring systems, survival endpoints, and reproducibility assessment are recommended before routine incorporation into breast carcinoma reporting protocols.