Numerous lymph node metastases in early gastric cancer without preoperatively enlarged lymph nodes: a case report

Background According to the 2018 Japanese gastric cancer treatment guidelines (ver. 5), a reduced extent of lymphadenectomy (D1 or D1+) is indicated for cT1 N0 tumors that do not meet the criteria for endoscopic resection. However, early gastric cancer with multiple lymph node metastases is not unknown, and cases have been reported. We report a case of a patient with early gastric cancer and numerous nodal metastases who underwent laparoscopic proximal gastrectomy based on a preoperative diagnosis of T1 N0. Case presentation A 69-year-old woman underwent emergent endoscopic hemostasis for massive hematemesis of the stomach, and endoscopic examination showed ulceration with a visible vessel. Pathological biopsy examination of the ulcer identified poorly differentiated adenocarcinoma with signet ring cells. The patient was diagnosed with early gastric cancer that was not indicated for endoscopic resection because of the ulceration and histological type. Endoscopic ultrasound showed that the third layer was poorly demarcated at the ulcer scar, indicating invasion to the submucosal layer. Computed tomography did not reveal enlarged lymph nodes or distant metastasis. The preoperative diagnosis was early gastric cancer of the fundus without nodal metastasis, and laparoscopic proximal gastrectomy with D1+ lymphadenectomy was performed. The initial postoperative pathological diagnosis was intramucosal carcinoma without lymphovascular invasion; however, the presence of 26 lymph node metastases was revealed unexpectedly. Additional pathological examination of more resected specimens transected every 2-3 mm revealed that only one lesion contained a small number of cancer cells in the lymphatic duct below the muscularis mucosa. Conclusions We report a case of early gastric cancer with 26 nodal metastases in which lymph node involvement was not identified prior to surgery. These findings indicate that the extent of lymphadenectomy and the surgical procedure should be carefully decided even in cT1 N0 early gastric cancer when several risk factors for lymph node metastasis are present.