[Identification of sentinel lymph node with patent blue V in patients with cutaneous melanoma].

Regional lymphadenectomy in patients with cutaneous malignant melanoma in stages I-U AJC/UICC has not demonstrated improvement either in loco-regional control or in survival. The results of the lymphatic mapping technique have demonstrated that on identifying the sentinel node, the group of patients with microscopic nodal metastases can be selected for regional treatment. We performed the intraoperative lymphatic mapping technique with 1 ml of blue patent V by intradermal injection just around the primary melanoma; after injecting the dye we incised the nodal skin region, identifying the sentinel node by its blue color. The histologic examination, by frozen section of this node, determines whether or not to proceed with a formal lymphadenectomy. We calculated the sensitivity of the dye for the identification of the sentinel node and the Pearson's test was performed between the intraoperative histologic study and the definite pathological result. Thirty one lymphatic mappings were performed in 29 patients with stages I-II malignant cutaneous melanoma. The sentinel node was found in 26/31 explored lymphatic zones, and in 5, it was not found, sensitivity of 84%; 23/26 sentinel nodes were negative and only 3/26 were metastatic in frozen section. The Pearson's test result was 0.78 with a predictive value of 92%. The blue patent V intraoperative lymphatic mapping technique in patients with malignant cutaneous melanoma provided a great sensitivity to identify the sentinel node and allows the identification of patients with high risk of microscopic nodal metastases.