Single skip metastasis in sentinel lymph node: In an early gastric cancer

Lymph node status is considered a key prognostic and predictive factor in patients with gastric cancer (GC). Although there is a practical approach to the intraoperative detection of sentinel lymph nodes (SLNs), such a procedure is not included in the European surgical protocol. In this report, we present a practical approach to SLN mapping in a representative case with early gastric cancer (EGC). A 74-year-old female was hospitalized with an endoscopically observed, superficially ulcerated tumor located in the antral region. Subtotal gastrectomy with D2 lymphadenectomy and SLN mapping was performed by injecting methylene blue dye into the peritumoral submucosal layer. An incidentally detected blue-stained lymph node located along the middle colic artery was also removed. This was detected 40 min after injection of the methylene blue. Histopathologic examination showed a pT1b-staged well-differentiated HER-2-negative adenocarcinoma. All of the 41 LNs located at the first, third, and fifth station of the regional LN compartments were found to be free of tumor cells. The only lymph node with metastasis was located along the middle colic artery and was considered a non-regional lymph node. This incidentally identified skip metastasis indicated stage IV GC. A classic chemotherapy regimen was given, and no recurrences were observed six months after surgery. In this representative case, low-cost SLN mapping, with a longer intraoperative waiting time, totally changed the stage of the tumor in a patient with EGC.