Giant extra gastrointestinal stromal tumor of lesser omentum obscuring the diagnosis of a choloperitoneum

INTRODUCTIONHerein we present an extremely rare case of a giant extra gastrointestinal stromal tumor (EGIST) of the lesser omentum obscuring the diagnosis of a choloperitoneum.PRESENTATION OF CASEA 79 years old female was admitted to our hospital with symptoms of vomiting and epigastric pain. Abdominal computer tomography revealed a sizable formation that was diagnosed as a tumor of the pancreas. In laparotomy, a choloperitoneum was diagnosed as the cause of patient's symptoms. A tumor adherent firmly to the lesser curvature of stomach was also discovered. Cholecystectomy and subtotal gastrectomy were performed. Histologically, the tumor was diagnosed as a EGIST of the lesser omentum. The patient did not receive any adjuvant therapy and after two years of follow up she is without any recurrence.DISCUSSIONOmental EGISTs may remain clinically silent despite the large tumor's size. It is difficult to differentiate a EGIST in the lesser omentum from a GIST of the lesser curvature of the stomach, despite the use of advanced radiological imaging techniques. Our case of a giant EGIST of lesser omentum obscuring the diagnosis of acute choloperitoneum is the only one reported in literature.CONCLUSIONEGISTs that arise from the omentum are very rare and complete surgical resection is the only effective treatment approach. Adjuvant therapy following resection of localized disease has become standard of care in high risk cases.