title: Demonstration of second-tier lymph nodes during preoperative lymphoscintigraphy for melanoma: incidence varies with primary tumor site.
abstract: BACKGROUND
  Preoperative cutaneous lymphoscintigraphy (LS) to identify sentinel (first-tier) lymph nodes was performed in 250 consecutive melanoma patients before wide local excision only or wide local excision with sentinel node biopsy.
  
  
  METHODS
  The location of the sentinel nodes was marked on the overlying skin in all patients. Whether or not tracer was present in second-tier lymph nodes on the delayed scans was recorded for each patient and related to the lesion site at which the tracer had initially been injected. For 100 consecutive patients the rate of tracer movement through the lymphatic channels was compared to the incidence of second-tier drainage.
  
  
  RESULTS
  Second-tier nodes were visualized in all patients with melanomas on the leg and thigh, and in almost all patients with melanomas on the forearm and hand, but were seen less often in patients with more centrally located melanomas. There was a significant correlation between the rate of lymph flow and the incidence of demonstrable second-tier drainage.
  
  
  CONCLUSIONS
  The results suggest that the physiology of the lymphatic system varies depending on the origin of the lymphatic vessel. These findings have important implications for application of the sentinel node biopsy technique in individual patients.
authors.affiliation: Nuclear Medicine and Diagnostic Ultrasound, Camperdown, New South Wales, Australia.
authors.forename: R F
authors.initials: RF
authors.lastname: Uren
authors.forename: R B
authors.initials: RB
authors.lastname: Howman-Giles
authors.forename: J F
authors.initials: JF
authors.lastname: Thompson
mesh_terms: D000965:Antimony; D001132:Arm; D006801:Humans; D007866:Leg; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000556:secondary / Q000601:surgery; D009333:Neck; D011877:Radionuclide Imaging; D017556:Technetium Compounds
chemical_list: D017556:Technetium Compounds; C019096:technetium Tc 99m antimony sulfide; D000965:Antimony