[Detection of lymphatic metastasis from malignant melanoma after identification of the sentinel node by preoperative lymphoscintigraphy and intraoperative radioisotopic detection].

OBJECTIVES

The aim of this study was to evaluate the detection of the first lymph node draining the primary tumour site, using a radioisotopic mapping alone and to determine whether a preoperative lymphoscintigraphy using technetium sulfur colloid and a hand-held gamma detecting probe could improve the detection of the sentinel lymph node (SLN) in melanoma.

PATIENTS AND METHOD: From January to December 1998, 36 patients with a cutaneous melanoma larger than 0.75 mm, stage I TNM were included in this prospective study. Mean Breslow was 1.85 mm. The distribution of melanoma was head and neck (n = 9), trunk (n = 7), upper extremities (n = 4), lower extremities (n = 16). Preoperative lymphoscintigram and intraoperative detection were used. The first hot lymph node was supposed to be the SLN.

RESULTS

In all cases, a lymph node was found and nine patients had more than one SLN (average number of SLN per patient: 1.25). Aberrant drainages were found in seven patients (19.4%): 1 in-transit lymph node, three paradoxical bassins, three bypasses). Four out of 36 patients had lymph node metastases and underwent elective lymph node dissection.

CONCLUSION

The radio-isotopic technique used alone for the identification of the SLN is efficient in melanoma with a 100% detection rate in this short series.