Implication of an Intramammary Sentinel Lymph Node in Breast Cancer: Is This a True Sentinel Node? A Case Report

BACKGROUND: Intramammary lymph nodes (ILN) are often diagnosed by final histological examination. Recently, sentinel lymph node biopsy (SLNB) has been developed as a new standard in the treatment of breast cancer. However, reports describing intramammary sentinel nodes (ISLNs) are relatively rare, and the clinical significance of metastases in ISLNs is still unclear. CASE REPORT: We herein report a patient with breast cancer with an ISLN that was detected prior to surgery. In the current case, the ISLN contained foci of carcinoma, but the axillary SLNs (aSLN) did not contain such foci. Previous reports related to ISLNs and aSLNs, including our case, are reviewed. Interestingly, there was no case with negative ISLNs and positive aSLNs. CONCLUSIONS: The current and previous cases have shown that axillary lymph node dissection (ALDN) might rely on the aSLN status but not on the ISLN status. The effect on the prognosis or clinical significance in cases with positive ISLNs has not been fully elucidated. Cases of ISLNs found by SLN navigation are discussed in relation to their clinical significance.