Lack of effect of particle size on the identification of the sentinel node in cutaneous malignancies

Radiotracers have become a routine technical component of the new procedure of intraoperative lymphatic mapping and selective lymphadenectomy. Because different colloids have differing physicochemical properties, their distribution and uptake may be different. For this reason, the optimal colloid to identify and localize the sentinel node remains controversial.

Nineteen consecutive patients with cutaneous malignancies underwent diagnostic lymphoscintigraphy with 99mTc-labeled human serum albumin (99mTc-HSA) and preoperative lymphoscintigraphy with 99mTc-labeled sulfur colloid (99mTc-SC). The results of intraoperative lymphatic mapping and selective lymphadenectomy were reviewed.

Intraoperative lymphatic mapping and selective node dissection were successful in 21 of 22 lymphatic basins (18 of 19 patients). There was excellent correlation between the "hot" marker placed on the skin surface when 99mTc-HSA was used compared with the use of 99mTc-SC. In 20 of 21 lymphatic basins the sentinel node both was "hot" and was stained with isosulfan blue.

No discernible difference between the ability to localize in the sentinel node with these two radiocolloids was identified. For logistical reasons, 99mTC-SC appears to be the colloid of choice in intraoperative lymphatic mapping.