title: The role of interval nodes in sentinel lymph node mapping and dissection for melanoma patients.
abstract: In sentinel node (SN) biopsy, an interval SN is defined as a lymph node or group of lymph nodes located between the primary melanoma and an anatomically well-defined lymph node group directly draining the skin. As shown in previous reports, these interval SNs seem to be at the same metastatic risk as are SNs in the usual, classic areas. This study aimed to review the incidence, lymphatic anatomy, and metastatic risk of interval SNs.
  
  
  METHODS
  SN biopsy was performed at a tertiary center by a single surgical team on a cohort of 402 consecutive patients with primary melanoma. The triple technique of localization was used-that is, lymphoscintigraphy, blue dye, and gamma-probe. Otolaryngologic melanoma and mucosal melanoma were excluded from this analysis. SNs were examined by serial sectioning and immunohistochemistry. All patients with metastatic SNs were recommended to undergo a radical selective lymph node dissection.
  
  
  RESULTS
  The primary locations of the melanomas included the trunk (188), an upper limb (67), or a lower limb (147). Overall, 97 (24.1%) of the 402 SNs were metastatic. Interval SNs were observed in 18 patients, in all but 2 of whom classic SNs were also found. The location of the primary was truncal in 11 (61%) of the 18, upper limb in 5, and lower limb in 2. One patient with a dorsal melanoma had drainage exclusively in a cervicoscapular area that was shown on removal to contain not lymph node tissue but only a blue lymph channel without tumor cells. Apart from the interval SN, 13 patients had 1 classic SN area and 3 patients 2 classic SN areas. Of the 18 patients, 2 had at least 1 metastatic interval SN and 2 had a classic SN that was metastatic; overall, 4 (22.2%) of 18 patients were node-positive.
  
  
  CONCLUSIONS
  We found that 2 of 18 interval SNs were metastatic: This study showed that preoperative lymphoscintigraphy must review all known lymphatic areas in order to exclude an interval SN.
authors.affiliation: Department of Visceral Surgery, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. maurice.matter@chuv.ch
authors.forename: Maurice
authors.initials: M
authors.lastname: Matter
authors.forename: Marie
authors.initials: M
authors.lastname: Nicod Lalonde
authors.forename: Mohamed
authors.initials: M
authors.lastname: Allaoua
authors.forename: Ariane
authors.initials: A
authors.lastname: Boubaker
authors.forename: Danielle
authors.initials: D
authors.lastname: Liénard
authors.forename: Oliver
authors.initials: O
authors.lastname: Gugerli
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Cerottini
authors.forename: Hanifa
authors.initials: H
authors.lastname: Bouzourene
authors.forename: Angelika
authors.initials: A
authors.lastname: Bischof Delaloye
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Lejeune
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000175:diagnosis* / Q000556:secondary*; D008875:Middle Aged; D011877:Radionuclide Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*