[A Case of a Submucosal Tumor-Like Gastric Cancer That Needed to Be Distinguished from Gastric Metastasis of Rectal Cancer].

A 56-year-old man who underwent a radical operation and adjuvant chemotherapy for recurrent rectal cancer had been followed-up and had no recurrence for one and a half years. Thereafter, CT and upper endoscopy showed a submucosal tumor with a central recess developing in the stomach wall. It was suspected that the gastric tumor was either a metastasis of rectal cancer or a submucosal tumor-like gastric cancer. We performed a radical operation to remove the lesion. In the resected specimen, immunohistopathological findings including HER2 status suggested that the gastric tumor was a primary gastric cancer resembling a submucosal tumor.