Incremental Diagnostic Value of Pancytokeratin Immunohistochemistry in Sentinel Lymph Node Assessment for Breast Cancer

Precise detection of sentinel lymph node metastasis is essential for staging early breast cancer. While routine histology and cytology remain standard in many centers, the additional diagnostic value of universal immunohistochemistry in resource-limited oncology systems remains underreported. The objective of this study was to quantify the incremental diagnostic contribution of pancytokeratin immunohistochemistry compared with conventional pathological assessment and explore clinicopathological predictors of nodal involvement. A secondary analysis was performed on a prospective cohort of 20 women with invasive breast carcinoma undergoing sentinel lymph node biopsy in Misrata (2023–2025). Nodes were examined using intraoperative touch imprint cytology, serial hematoxylin-eosin histology, and pancytokeratin immunohistochemistry. Immunohistochemistry was treated as the reference standard. Diagnostic sensitivities and exploratory associations between nodal metastasis and tumor characteristics were analyzed. Sentinel lymph node metastases were identified in 4 of 20 patients (20%). Conventional cytology and routine histology detected three macrometastatic cases but failed to identify one micrometastasis, yielding a sensitivity of 75%. Pancytokeratin immunohistochemistry detected all metastatic deposits (100%). Higher nodal positivity trends were observed in tumors >2 cm, Nottingham grade 3 tumors, and Ki-67 ≥30%, though statistical significance was limited by cohort size. Universal pancytokeratin immunohistochemistry substantially improves the detection of low-volume sentinel node metastasis and may prevent pathological understaging in developing surgical oncology programs. These findings support integration of routine immunohistochemical evaluation into standardized sentinel node protocols.