What happened, in summary

A 78-year-old man had undergone distal gastrectomy for an early gastric cancer 9 years earlier. During routine follow-up, endoscopy found a new depressed tumor in the remaining stomach. Biopsy suggested well- to moderately differentiated adenocarcinoma, and CT showed no lymph-node metastasis. Because the lesion appeared confined to the inner stomach lining, endoscopic submucosal dissection was performed.

The removed tumor proved more complex than the initial biopsy suggested. About 60% was neuroendocrine carcinoma and 40% was well-differentiated adenocarcinoma, making it a gastric mixed adenoneuroendocrine carcinoma. The adenocarcinoma portion remained in the mucosa, while the neuroendocrine component extended into the deep submucosa. Lymphatic invasion was present, and the vertical resection margin contained neuroendocrine carcinoma.

Because of those higher-risk findings, he underwent total gastrectomy with lymph-node dissection. No residual cancer cells were found in the additional surgical specimen.

One year after surgery, follow-up endoscopy and CT showed no local recurrence or lymph-node metastasis. At that follow-up, no recurrent disease was identified.