sentinel lymph node biopsy correctly predicts regional lymph node recurrence in trunk malignant melanoma with multiple drainage basins

we report a young male with an initial excisional biopsy report of melanoma of the lower back, referred to our hospital for complete excision and sentinel lymph node (sln) biopsy.  four peritumoral intradermal tc-99m phytate injection was performed and slns were detected in both axillary and right inguinal regions. on the biopsy only the right axillary sln was metastatic leading to right axillary lymph nodes dissection 6 days later. no other surgical intervention was done for two other lymphatic drainage basins. on follow up the patient noted a right axillary mass with highly suspicious ultrasound findings. metastatic work up was negative. second axillary lymph node dissection confirmed conglomerated lymph nodes metastases in this area. multiple drainage basins in the trunk melanoma are common and many authors have concern about changing in lymphatic drainage pattern after sln biopsy and surgical manipulation. this case showed correct initial diagnosis of involved lymph nodes in one out of three lymphatic drainage basins, and also correctly predicts regional recurrence in the same location.