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To assess the incidence of nonmajor lymphatic basin sentinel nodes in patients with cutaneous melanoma in order to propose a correct nomenclature and inform appropriate surgical management.This was a retrospective review of 1,045 consecutive patients with cutaneous melanoma who underwent sentinel lymph node biopsy and dynamic lymphoscintigraphy to identify sentinel node site. Nonmajor drainage sites were classified as uncommon (located in a minor lymphatic basin along the lymphatic drainage to a major classical nodal basin) or interval (located anywhere along the lymphatics between the primary tumor site and the nearest lymphatic basin) sentinel nodes.Nonclassical sentinel nodes were identified in 32 patients (3.0 %). Uncommon sentinel nodes were identified in 3.2 % (n = 17) of trunk melanoma primary disease and in 1.5 % (n = 7) of upper and lower extremity sites. Interval sentinel nodes were identified in 1.3 % (n = 7) of trunk primary lesions, with none from upper and lower extremities melanomas. The incidence of tumor-positive sentinel nodes was 24.1 % (245 of 1,013) in classical sites and 12.5 % (4 of 32) in uncommon/interval sites.The definition of uncommon and interval sentinel nodes allows the identification of different lymphatic pathways and inform appropriate surgical treatment. Wider experience with uncommon/interval sentinel nodes will better clarify the clinical implications and surgical management to be adopted in the management of uncommon and interval sentinel node sites.

Although sentinel node biopsy (SNB) has become standard of care in patients with melanoma, its use in patients with thin or thick melanomas remains a matter of debate.This was a retrospective analysis of patients with thin (≤1 mm) or thick (≥4 mm) melanomas who underwent SNB at two Italian centers between 1998 and 2011. The associations of clinicopathologic features with sentinel lymph node positive status and overall survival (OS) were analyzed.In 492 patients with thin melanoma, sentinel node was positive for metastatic melanoma in 24 (4.9 %) patients. No sentinel node positivity was detected in patients with primary tumor thickness0.3 mm. Mitotic rate was the only factor significantly associated with sentinel node positivity (p = 0.0001). Five-year OS was 81 % for patients with positive sentinel node and 93 % for negative sentinel node (p = 0.001). In 298 patients with thick melanoma, 39 % of patients had positive sentinel lymph nodes (median Breslow thickness 5 mm). In patients with positive sentinel node, 93 % had mitotic rate1/mm(2). Five-year OS was 49 % for patients with positive sentinel lymph nodes and 56 % for patients with negative sentinel nodes (p = 0.005).The rate of sentinel node positivity in patients with thin melanoma was 4.9 %. The only clinicopathologic factor related to node positivity was mitotic rate. Given its prognostic importance, SNB should be considered in such patients. SNB should also be the standard method for melanoma ≥4 mm, not only for staging, but also for guiding therapeutic decisions.

Sentinel lymph node biopsy is widely accepted as standard care in melanoma despite lack of pertinent randomized trials results. A possible pitfall of this procedure is the inaccurate identification of the sentinel lymph node leading to biopsy and analysis of a nonsentinel node. Such a technical failure may yield a different prognosis. The purpose of this study is to analyze the incidence of false negativity and its impact on clinical outcome and to try to understand its causes.The Melanoma Data Base at National Cancer Institute of Naples was analyzed comparing results between false-negative and tumor-positive sentinel node patients focusing on overall survival and prognostic factors influencing the clinical outcome.One hundred fifty-one cases were diagnosed to be tumor-positive after sentinel lymph node biopsy and were subjected to complete lymph node dissection. Thirty-four (18.4%)patients with tumor-negative sentinel node subsequently developed lymph node metastases in the basin site of the sentinel procedure. With a median follow-up of 42.8 months the 5-year overall survival was 48.4% and 66.3% for false-negative and tumor-positive group respectively with significant statistical differences (P.03).The sensitivity of sentinel lymph node biopsy was 81.6%, and a regional nodal basin recurrence after negative-sentinel node biopsy means a worse prognosis, compared with patients submitted to complete lymph node dissection after a positive sentinel biopsy. The evidence of higher number of tumor-positive nodes after delayed lymphadenectomy in false-negative group compared with tumor-positive sentinel node cases, confirmed the importance of an early staging of lymph nodal involvement. Further data will better clarify the role of prognostic factors to identify cases with a more aggressive biological behavior of the disease.