Multiple gastrointestinal metastasis after endoscopic submucosal dissection for poorly differentiated gastric adenocarcinoma

A 76-year-old man had a diagnosis of double primary cancers consisting of poorly differentiated esophageal squamous cell carcinoma (ESCC) invading the submucosa and poorly differentiated gastric adenocarcinoma (GAC) invading the submucosa. The clinical stage of both ESCC and GAC was T1N0M0 stage I. The tumor diameter of ESCC and GAC was 20 mm and 25 mm, respectively. We performed chemoradiotherapy for ESCC. Chemotherapy consisted of nedaplatin in an intravenous dose of 90 mg/m² on day 1 and 5-fluorouracil in an intravenous dose of 800 mg/m² on days 1–5, repeated every 4 weeks for two cycles. Radiotherapy consisted of 50.4 Gy in 28 fractions for ESCC. GAC was down-staged after chemoradiotherapy for ESCC and was treated by endoscopic submucosal dissection (ESD). The tumor was histopathologically confirmed to be down-staged to intramucosal cancer with a diameter of 18 mm and no evidence of lymphovascular invasion and ulceration. Multiple metastasis occurred in the stomach, the small intestine and the colorectum after ESD. ESD is not a curative treatment even if chemotherapy is effective for poorly differentiated GAC invading the submucosa. Multiple gastrointestinal metastasis may be a unique recurrence pattern after ESD for such a lesion.