Sentinel node biopsy in malignant melanoma using stannous phytate and .GAMMA.-probe.

We report our experience of sentinel lymph node biopsy in malignant melanoma cousing patent blue V dye, preoperative lymphoscintigrapy and handheld gamma probe. Patients underwent preoperative lymphoscintigraphy with99mTc-labeled stannous phytate a day before operation. The patients subsequently underwent intraoperative lymphatic mapping and selective lymph node dissection with patent blue dye and radiopharmaceutical agent. A handheld gamma probe determined the radioactive counts over the blue stainned lymph node and the other nodes mapped by lymphoscintigraphy. The single injection of99mTc-labeled stannous phytate was effective in both preoperative lymphoscintigraphy and handheld gamma probeguided intraoperative determination of sentinel lymph nodes. The dissected lymph nodes were assessed by both intraoperative frozen section investigation and formaline-fixed section stained with hematoxylin and eosin and HMB-45. We failed to detect micrometastases by frozen section in 3 of 3 positive sentinel lymph nodes from 2 patients.Although the addition of radiopharmaceutical agents serves as a useful adjunct, the blue dye technique remains the criterion standard for selective lymph node dissection. The frozen section analysis is not recommended for determination of subsequent therapeutic lymph node dissection. [Skin Cancer (Japan) 2001; 16: 205-210]