Interval nodes: the forgotten sentinel nodes in patients with melanoma.
BACKGROUND
Any sentinel lymph node that receives lymph drainage directly from a primary melanoma site, regardless of its location, may contain metastatic disease. This is true even if the sentinel node does not lie in a recognized node field. Interval (in-transit) nodes that lie along the course of a lymphatic vessel between a primary melanoma site and a recognized node field are sometimes seen during lymphatic mapping for sentinel node biopsy. If drainage to such interval nodes is ignored by the surgeon during sentinel node biopsy, metastatic melanoma will be missed in some patients.


OBJECTIVE
When lymph drains directly from a cutaneous melanoma site to an interval node, that sentinel node has the same chance of harboring micrometastatic disease as a sentinel node in a recognized node field.


METHODS
Preoperative lymphoscintigraphy with technetiumTc 99m antimony trisulfide colloid was performed to define lymphatic drainage patterns and, since 1992, to locate the sentinel lymph nodes for surgical biopsy or for permanent skin marking of their location with point tattoos.


METHODS
Melanoma unit of a university teaching hospital.


METHODS
A total of 2045 patients with cutaneous melanoma were studied in 13 years.


RESULTS
Interval nodes were found in 148 patients (7.2%). The incidence of interval nodes varied with the site of the primary melanoma. Interval nodes were more common with melanomas on the trunk than with those on the lower limbs. Micrometastatic disease was found in 14% of interval nodes that underwent biopsy as sentinel nodes. This incidence is similar to that found in sentinel nodes located in recognized node fields, confirming the potential clinical importance of interval nodes.


CONCLUSIONS
Interval nodes should be removed surgically along with any additional sentinel nodes in standard node fields if the sentinel node biopsy procedure is to be complete. In some patients, an interval node will be the only lymph node that contains metastatic disease.
Uren
R F
RF
Nuclear Medicine and Diagnostic Ultrasound, RPAH Medical Centre, 100 Carillon Ave, Suite 206, Newtown, New South Wales 2042, Australia. ruren@mail.usyd.edu.au
Howman-Giles
R
R
Thompson
J F
JF
McCarthy
W H
WH
Quinn
M J
MJ
Roberts
J M
JM
Shaw
H M
HM
D005260:Female; D006801:Humans; D015994:Incidence; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000556:secondary / Q000601:surgery; D011300:Preoperative Care; D011379:Prognosis; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D013671:Technetium Tc 99m Sulfur Colloid
D013671:Technetium Tc 99m Sulfur Colloid