Sentinel lymph node biopsy procedure for malignant melanoma. The blue dye (Lymphazurin blue) that is injected in the vicinity of the tumor traverses the lymphatic channels draining the area and accumulates in the sentinel lymph node. For additional details on sentinel lymph node biopsy, Click here. Image courtesy of: Eddy Hsueh, MD, Professor of Surgery, Saint Louis University, St. Louis, Missouri, USA. Used with permission.