Rectal metastasis of gastric cancer: a case report

The most common metastatic sites of gastric cancer include the liver, peritoneum, lung, and bone. However, there is a lack of relevant clinical reports regarding rectal metastasis. Herein, we report the rare case of a patient with gastric cancer who developed rectal metastasis. A 57-year-old male patient was diagnosed with gastric cancer and underwent a radical gastrectomy in January 2016, followed by eight cycles of adjuvant chemotherapy. The patient subsequently developed a rectal mass in March 2021. He was diagnosed with rectal adenocarcinoma and underwent surgical resection of the rectal tumor. A mass was then found in the abdominal wall in September 2021 and was resected. Specimens obtained from the three surgeries were reviewed, and the rectal tumor and the mass in the abdominal wall were both found to be metastatic tumors from the gastric cancer. Metastasis of gastric cancer to the rectum is rare, but it is important to differentiate between rectal metastasis and primary rectal cancer to help avoid unnecessary treatment.