An Case of Perforated Gastric Gastrointestinal Stromal Tumor (GIST) Complicated by Bacteremia and Liver Abscess

Abstract

Introduction: GIST is one of the most common mesenchymal tumors in the gastrointestinal (GI) tract closely related to the interstitial cells of Cajal and generally express c-KIT (CD114), a tyrosine kinase receptor. The most common locations are the stomach (40%-60%), small intestine (30%-40%), anorectum (7%), colon, and esophagus, as well as in extra-GI locations such as mesentery, omentum, and peritoneum(< 5%). We report a case of metastatic and perforated gastric GIST complicated by streptococcus bacteremia and hepatic abscess. Body: A 73 year old male presented with generalized weakness. At admission, he was febrile to 100.7F with RUQ tenderness. Imaging revealed peritoneal implants, a mass like process with air inseparable from the wall of the stomach near the fundus measuring 10 cm and left lobe liver mass measuring 6.4 cm (Fig 1). The patient was started on broad spectrum antibiotics. Blood cultures grew streptococcus intermedius (viridans group). Liver mass biopsy specimen revealed fragments of necrotic tissue and liver parenchyma without viable tumor. Endoscopy revealed a ˜3 cm perforated ulcer which appeared to be communicating with fundal mass (Fig 2). Pathologic showed poorly differentiated tumor with epithelioid and stromal features, CD117 +, CD34 +, cytokeratin - and CD45- compatible with GIST. Patient was ruled out for endocarditis and received antibiotics for total of 6 weeks. The patient was managed non surgically and repeat imaging (Fig 3) at 3 months showed marked improvement on Imatinib.Figure 1Figure 2Figure 3Discussion: GIST are well circumscribed tumors which may exhibit an exophytic or an endophytic pattern compromising bowel lumen patency. Mucosal necrosis and ulceration can be seen in GISTs with an endophytic component. Approximately 10-30% of GISTs are malignant and have intra-abdominal spread. The propensity of a GIST to become malignant depends on the primary anatomic site. Regardless of size and malignancy status, GISTs have a tendency to disrupt GI mucosal integrity, forming a conduit through which colonizing bacteria gain access to the portal and systemic circulation, resulting in bacteremia and liver abscess. A hematogenous source should be suspected if streptococcus or staphylococcous species are identified. Cystic degeneration, necrosis, and focal hemorrhage have been described in larger GIST accounting for the observed central necrotic cavitation resulting in fistulous connections with nearby structures, including the gastric lumen. There are only few case reports of a perforated gastric GIST, despite a higher overall incidence of GISTs in stomach. In our case, we suspect that the infection seeded from the GIST and should be included in the differential diagnosis in patients with suspected abdominal neoplasm and bacteremia.