Popliteal sentinel lymph node biopsy is important in malignant melanoma of the distal lower extremities: a case report of acral lentiginous melanoma with simultaneous inguinal and popliteal lymph node micrometastases

摘要

Sentinel lymph node (SLN) biopsy has been used as a diagnostic and prognostic indicator for a number of tumors, including malignant melanoma. However, positive popliteal SLN are rare. We present a patient with a malignant melanoma on the lateral aspect of his foot, who had SLN metastases in both popliteal and inguinal regions. A 69-year-old Japanese male was referred to our hospital for a more than 3 year history of a pigmented lesion on his left foot. He had been receiving maintenance hemodialy-sis for chronic renal failure associated with hypertension for 12 years. A clavus-like pigmented nodule was surrounded by multiple irregularly shaped macules on the plantar-lateral aspect of his left foot (figure 1A). The entire lesion was 45x37 mm in size. Lymph nodes in the inguinal and popliteal areas were not palpable, which was confirmed by echogram and CT scan.