In simple words: The doctor injects a special dye near the tumor to find the first lymph nodes the cancer might spread to. These "sentinel" nodes are then checked for cancer cells.

This add-on code describes the intraoperative identification of sentinel lymph nodes, which are the first lymph nodes to receive lymphatic drainage from a tumor.The procedure involves injecting a non-radioactive dye into the tissues surrounding the tumor site. The dye is then tracked visually to locate the sentinel lymph nodes, which are then typically biopsied or excised for pathological examination to determine if the cancer has spread. This procedure is often performed in conjunction with other surgical procedures like tumor resection or lymph node biopsy.

Example 1: A patient with breast cancer undergoes a lumpectomy (19301) and sentinel lymph node mapping (38900) using blue dye to assess the extent of cancer spread., A patient with melanoma undergoes wide local excision of the lesion and sentinel lymph node mapping (38900) with non-radioactive dye is performed to determine if the cancer has spread to the lymph nodes., A patient with vulvar cancer undergoes a wide local excision. The surgeon attempts sentinel lymph node mapping using blue dye (38900) but is unable to identify a sentinel node. A complete inguinofemoral lymphadenectomy (38770) is performed.

The operative report should clearly document the injection of the non-radioactive dye, the identification (or attempted identification) of the sentinel lymph node(s), the location of the injection site and sentinel nodes, and any associated procedures performed (e.g., biopsy, excision).If sentinel nodes are not identified, the documentation should detail the methods used and the extent of the search.