These data support the fact that cutaneous lymphatic drainage patterns are maintained in patients with grossly involved basins, thus buttressing the idea that the SLN is the node most likely to develop metastatic disease. Gross disease in the basin does not significantly alter cutaneous lymphatic flow into the regional basin, as the sentinel lymph node identified under these circumstances is the same as with the grossly involved node. Preoperative lymphoscintigraphy in patients who present with grossly involved nodes in one basin may identify other regional basins with micrometastatic disease and deserves further study in this setting.