Abstract
In patients with malignant melanoma, the site for lymph node dessection is now determined by the primary site of the tumor according to the standard of UICC. However, sometimes it is difficult to predict accurate lymph node drainage because the tumor occupies two or three lymph node areas, which Sappey called “Watershed” areas, such as the midline of the trunk. We applied the technique of sentinel node biopsy (SNB) using patent blue dye for the patient with malignant melanoma of the under back. It was possible to detect the lymph node drainage flowing not only to the groin area but also to the axillar area. We consider that SNB is one of the effective methods to determine the lymph node drainage of the tumor in so-called “Watershed” areas. [Skin Cancer (Japan) 2002; 17: 31-37]
