Sentinel Lymph Node: Clinicopathologic Features

Abstract

The sentinel lymph node (SLN) is frequently the first node in the lymphatic basin that receives drainage from an anatomic region and is immunologically responsible for that region. Sentinel lymph node biopsy (SLNB) remains the standard of care for the assessment of clinically negative axillary lymph nodes in patients with invasive breast carcinomas. Accurate diagnosis of a SLNB can direct the surgeon with regard to the need for axillary dissection (AD), and it can affect post-operative treatment decisions, including decisions about radiation therapy. Furthermore, an accurate negative diagnosis on SLNB can spare the patient the increased risk of lymphedema that accompanies AD or post-operative treatments. Its relatively low false negative rate of 5–10% and high sensitive rate of 90–95% in the detection of cancer to the lymph node basin has made this minimally invasive operation a standard. The idea that the SLN serves as a limited target sample of the axillary lymph nodes aroused an interest and trend toward increased inspection of the sentinel lymph node for detection of metastatic carcinoma by the pathologist though serial sections and/or immunohistochemistry.