Sentinel lymph node biopsy and melanoma: 2010 update: Part I - Sentinel lymph node biopsy for melanoma was introduced in the early 1990s as a minimally invasive method of identifying and pathologically staging regional lymph node basins in patients with clinical stage I/II melanoma. Numerous large trials have demonstrated that sentinel lymph node evaluation has utility in improving accuracy of prognostication and for risk stratifying patients into appropriate groups for clinical trials. However, there remains a great deal of controversy regarding the therapeutic role of removal of the remainder of locoregional lymph nodes should metastatic cells be identified in the sentinel node. This CME article will outline a brief history of the sentinel node concept before reviewing updates in surgical technique, histopathologic evaluation of nodal tissue, and cost effectiveness of sentinel node biopsy.Learning objectives: After completing this learning activity, participants should be able to describe the concept of sentinel lymph node biopsy, to discuss the risks and benefits associated with this procedure, and to summarize the role of sentinel lymph node biopsy in management of patients with melanoma. [JAAD]