Metastatic Gastric Signet Ring Cell Adenocarcinoma Presenting With Colonic Stenosis

Metastases to the colon are rare and may mimic other diseases such as inflammatory bowel disease. This differential diagnosis is often overlooked by endoscopists which leads to unnecessary diagnostic delay or inappropriate treatment. We present a case of a 54-year-old woman who presented with ascites. Malignant cells were demonstrated on cytologic examination of ascitic fluid, but no primary tumour or metastases were seen on computed tomography of the abdomen. On colonoscopy, an impassable stenosis was found in the transverse colon with scattered patches of oedematous colonic mucosa through to the mid-descending colon. Histological examination revealed scattered signet ring cells and the diagnosis of gastric signet ring cell adenocarcinoma was confirmed with subsequent gastroscopy. The correct and timely diagnosis of metastatic lesions to the colon requires a high index of suspicion and adequate mucosal sampling with multiple biopsies.