Low Probability of Lymphatic Drainage to Cloquet's Node Is of Limited Value as Indicator for Pelvic Lymph Node Dissection in Patients with Lower Limb Melanoma.

Background And Objectives: For patients with melanoma, the choice between an inguinal lymph node dissection (ILND) alone and both an ILND and a pelvic lymph node dissection (PLND) is controversial. Although Cloquet's node (CN) is considered the sentinel pelvic node, evaluation of this factor to predict pelvic node status has produced varied results. We investigated inguinal and pelvic lymphatic drainage patterns and focused on CN to clarify whether CN status could be an indicator of PLND.

Methods: Patients with primary cutaneous lower limb melanoma who underwent lymphatic mapping and sentinel lymph node biopsy (SLNB) using dynamic lymphoscintigraphy and SPECT/CT were retrospectively reviewed.

Results: Thirty-two patients underwent lymphatic mapping and SLNB. Each patient's CN was identified by SPECT/CT. A radioactive CN was detected in only 37.5% (12/32) of patients, and no lymphatic drainage to CN occurred in 62.5% (20/32). In 37.5% (12/32) of patients, the lymph drained directly from the inguinal to the pelvic nodes bypassing CN.

Conclusion: In melanoma patients, lymphatic drainage from the lower extremity does not always pass from the inguinal node to the pelvic nodes via CN. Tumor-negative status of CN alone is of limited value as an indicator for avoiding PLND.