Gastrointestinal Stromal Tumor at Ampulla of Vater Presented With Upper Gastrointestinal Bleeding

Abstract

Gastrointestinal stromal tumors (GISTs) is a mesenchymal tumor accounted for only one percent of primary GI cancer. An estimated 4,000 to 6,000 new cases of GISTs are diagnosed annually in the United States. Common locations of tumor are stomach and small intestine. GISTs at ampulla of Vater is extremely rare of only 12 cases per literature review. We presented the rare case of GISTs at ampulla of Vater presented with upper gastrointestinal bleeding. Sixty five years old female with history of diverticulitis status post laparoscopic sigmoidectomy, and gastroparesis presented with melena for 2 weeks. Upper endoscopy showed submucosal mass at the Ampulla of Vater (Figure 1). Biopsy showed normal duodenum. CT abdomen showed common bile duct dilation and 1 cm soft tissue nodule with peripheral enhancement within the third portion of duodenum. Endoscopic ultrasound confirmed submucosal mass (Figure 2), but the fine needle biopsy was complicated with bleeding, and the biopsy showed normal duodenum. ERCP with stent was placed in common bile duct to relieve the obstruction (Figure 3). MRI abdomen showed enhancing 1.7 x 1.5 cm mass within the periampullary region. She was referred to surgery. Open pancreatic sleeve duodenectomy was perfomed. Pathology revealed 2.3 cm GISTs with free margin and positive for CD 117, CD 34 and smooth muscle actin, negative for S100. No mitosis per fifty high power fields reported. No adjuvant chemotherapy is indicated. Melena is a common presentation of GISTs. However, diagnosis can be difficult because it is a submucosal mass which causes obtaining biopsy problematic. This patient was proved to have GISTs by expression of CD 117 which differentiate GISTs from leiomyoma and leiomyosarcoma. From previous reports, ulcerative lesion is concomitant findings in several cases but not presented in our case. Although GISTs at ampulla of Vater are rare, GISTs should be included in the differential diagnosis especially if the mass has an enhancement per CT scan which is characteristic of GISTs. Overall, prognosis is less favorable for small intestinal GISTs. Literatures reviews show that GISTs at Ampulla of Vater has fair prognosis. Almost all of them has no metastasis or lymph node involvement. Only one case had liver metastasis and died from hepatic failure.Figure: Upper endoscopy showed mass at ampulla of Vater.Figure: Endoscopic ultrasound confirmed submucosal mass.Figure: Side view from ERCP with stent.