Limitation of Using Ultrasonography After Positive Sentinel Lymph Node Biopsy in a Patient with Melanoma in the Detection of Lymph Node Metastasis

Recent studies have shown that complete lymph node dissection (CLND) performed immediately did not improve the overall survival in patients with sentinel lymph node (LN)-positive melanoma. According to these results, nodal observation with ultrasonography becomes standard. However, it still has some limitations for detection of metastatic LNs. A 74-year-old woman was diagnosed with acral lentiginous melanoma of her left sole. The sentinel LN was positive for metastasis, but she refused CLND. Sixteen months after operation, ultrasonography showed an abnormal LN in the inguinal region. There was no other abnormal LNs around the LN. We resected the abnormal LN. The resected LN was black in color, and the adjacent LN that showed normal appearance in ultrasonography was also black. A recent study showed only 6.6% sensitivity in preoperative ultrasonographic detection of metastatic melanoma in a LN. We should keep in mind the limitation of ultrasonography for detection of a metastatic LN.