Controversies in Surgical Pathology Minimal Involvement of Sentinel Lymph Node in Breast Carcinoma: Prevailing Concepts and Challenging Problems

Axillary lymph node (ALN) status remains the most important prognostic factor in breast carci-noma. In theory, and in practice, sentinel lymph node (SLN) is the first lymph node among the ALN to receive lymphatic drainage from a primary tu-mor. SLN biopsy is a less invasive, and a less morbid, alternative to ALN dissection for the staging of breast cancer; and it enables targeted, and efficient, pathological (histologic and immunohistochemical) evaluation for presence of metastatic tumor [1]. The cumulative evidence suggests that in appro-priately selected patients, SLN is an accurate predic-tor of ALN status, and is more predictive of ALN sta-tus, than any other factor, and non-SLNs are seldom involved if the SLN is tumor-free [2–4]. Based o