Radiographic and endoscopic regression of metastatic gastric cancer to the colon in the setting of 5-aminosalicylic acid use

Colonic metastases from gastric cancer are a rare phenomenon and sparsely reported in the literature. We report a case of a 59-year-old woman who presented with vague abdominal symptoms and initial computer tomography (CT) imaging suggestive of a colonic apple-core lesion with serial colonoscopic biopsies diagnostic of metastatic signet ring cell gastric adenocarcinoma. This case is unique given the evolving CT and endoscopic findings that suggested a regression in colonic wall thickening in the setting of 5-aminosalicylic acid (5-ASA) use prior to histologic diagnosis.