Feasibility of Performing Sentinel Lymph Node Biopsy (SLNB) after Mastectomy: A Case Report

Introduction: Previous mastectomy remains a contraindication to SLNB as normal drainage patterns of the breast can be disturbed. Patients diagnosed with DCIS on core biopsy and later found to have microinvasive or invasive carcinoma at the time of mastectomy are deprived of the opportunity for SLNB and need to undergo axillary dissection. We explored the option and feasibility of performing SLNB in a 39-year-old female who underwent a simple mastectomy without axillary sampling for extensive DCIS and later found to have microinvasive ductal carcinoma on permanent pathology. Results: Lymphatic mapping using subdermal injection of 99mTc-labeled sulfur colloid and blue dye led to the identification of five SLNs. Histopathologic examination showed no metastasis. Conclusion: SNLB is feasible in this setting. However, before its use is routinely adopted, its feasibility and accuracy has to be demonstrated in larger numbers of patients in whom a negative SLNB is followed by a completion axillary dissection.