Gastric adenocarcinoma metastasis to the rectum causing complete obstruction, a case report

Gastric adenocarcinoma is a leading cause of mortality worldwide. The most common sites of metastases are the liver, peritoneum, lungs, and bones. Cases have been described in the colon and rectum, but are very rare. This case report describes a patient in remission from diffuse signet ring cell type gastric adenocarcinoma with resection and chemoradiation close to 10 years prior to presenting with a near-obstructing rectal mass that was consistent with metastatic gastric adenocarcinoma. Gastric cancer spreads via hematogenous, lymphatic, peritoneal seeding, or local recurrence pathways. Given the length of time between initial presentation and eventual metastasis, the theory of dormancy is discussed and proposed as a possible cause in the delay of metastasis to the rectum. This highlights the importance of maintaining a high index of suspicion for recurrence and metastasis in a patient with a history of gastric cancer, who presents with a new obstructing rectal mass.