1892 Stomach Where the Sun Don’t Shine: A Rare Case of Gastric Adenocarcinoma Metastasizing to the Colon

Abstract

INTRODUCTION: Gastric cancer has been known to have a poor prognosis worldwide. It frequently leads to a metastatic disease, but rarely to the colon. CASE DESCRIPTION/METHODS: A 73-year-old male presented for a routine surveillance colonoscopy. He reported new onset constipation over the last 6-8 months that was not relieved by over-the-counter laxatives. He was found to have a stricture approximately 30 cm from the anal verge (Figure 1). This stricture was not seen on previous colonoscopy in 2014. He had a history of gastric adenocarcinoma 4 years ago, underwent a subtotal gastrectomy followed by chemotherapy and radiation and was closely followed in the oncology clinic. In addition, he also had a gastrointestinal stromal tumor (GIST) in the stomach. Histopathology was consistent with gastric adenocarcinoma (Figure 2). Widespread metastatic disease was found on PET scan (Figure 3). DISCUSSION: Although gastric cancer metastasizes to the liver, peritoneum and distant lymph nodes commonly, colon metastasis is rare and even rarer is sigmoid metastasis. We report a case of a patient with a change on bowel habits and was found to have gastric adenocarcinoma that has metastasized to the sigmoid colon causing a structuring lesion. In addition, both gastric adenocarcinoma and a concurrent GIST have been reported in literature. It has been suggested that C-KIT or PDGFR-a mutations can lead to both cancer types but more information on this subject is lacking in current literature. It appears though that having both types of cancers do not significantly influences symptoms or disease outcome.