What happened, in summary

A boy with longstanding immune and gastrointestinal disease had recurrent active gastritis from childhood and was initially thought to have Crohn's disease. His atrophic gastritis continued to progress despite intensive medical treatment.

At age 17, endoscopic biopsies identified an early invasive gastric adenocarcinoma. The cancer was not associated with EBV or CMV. He underwent total gastrectomy. Examination of the removed stomach showed chronic active gastritis with areas ranging from low- to high-grade dysplasia together with the invasive adenocarcinoma. Twenty lymph nodes were negative for cancer.

He reached complete remission after surgery. His underlying CTLA4-related illness did not disappear, and he continued to need intensive immunosuppressive treatment for active enterocolitis and other neurologic, blood and respiratory problems. Those therapies were directed at his immune disorder rather than the gastric cancer.

Despite the continuing non-cancer health burden, his gastric-cancer outcome was durable: he remained in complete remission for 7 years after the gastrectomy.