S2963 Synchronous Adenocarcinoma and Gastrointestinal Stromal Tumor in the Stomach: A Case Report

Abstract

INTRODUCTION: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal (GI) tract, however, their association with gastric malignancies is rare and remains poorly understood. Here we present a case of synchronous antral gastric adenocarcinoma and GIST tumor in the fundus. CASE DESCRIPTION/METHODS: A 55-year-old female patient was referred to our Gastroenterology clinic for intermittent abdominal discomfort and watery bowel movements of one-year duration. The patient denied any other significant medical or surgical history. She denied any history of tobacco, alcohol, or recreational drug use. No family history of malignancy was reported. Basic laboratory work up was unremarkable. A computed tomography scan of the abdomen showed a 4 cm gastric mass, and subsequently the patient underwent esophagogastroduodenoscopy (EGD) with endoscopic ultrasound which confirmed the finding of a submucosal mass in the fundus in addition to mild antral H. Pylori gastritis without metaplasia or dysplasia which was treated with confirmed eradication. Biopsy results showed CD117 and CD34 positive spindle cells with low mitotic activity consistent with GIST. Given the size of the mass, the patient underwent partial gastrectomy without complications. The patient’s symptoms persisted and hence underwent repeat EGD three months following her procedure which showed a 3 cm cratered antral ulcer with irregular margins, biopsy results confirmed mixed type HER-2 negative adenocarcinoma subsequently staged as T3N0M0. At the time of writing, the patient is receiving neoadjuvant chemotherapy with docetaxel, oxaliplatin and 5-fluorouracil with good response. DISCUSSION: GIST tumors are rare mesenchymal tumors of the GI tract (1%), most commonly seen in the stomach and synchronous gastrointestinal malignancies, particularly successive gastric adenocarcinoma, are even more scarcely reported. It is unclear whether there is a true association between these two entities or it is merely coincidental, however, careful endoscopic and histopathologic evaluation is recommended to identify those with synchronous malignancies as the treatment options and prognosis may subsequently change.