Review Article © Pol J Radiol, 2011; 76(3): 38-48 Figure 4. Axial CT scans of the abdomen. Duodenal GIST described as a pathology of the gallbladder: perforated cholecystitis or carcinoma of the gallbladder with cholelithiasis. Figure 5. Axial CT scans of the abdomen. Two examples of GISTs described as intraabdominal abscesses or inflammation of the small intestine wall. Figure 6. Axial CT scan and reconstruction of the study in the frontal plain. A case of small intestine GIST diagnosed as an ovarian tumor and resected in the gynecology ward. Figure 7. Axial CT scan and reconstruction in the frontal plain. A small intestine GIST reported as endometriosis • lack of characteristic features of GISTs that would dif- ferentiate them from other possible lesions of the gastro- intestinal wall, such as sarcomas, neuromas, carcinoid tumors, lymphomas, ectopic pancreas, etc, • areas of necrosis and cystic degeneration, often very large, result in misdiagnosis of intraabdominal abscess- es, inflamed intestinal loops, conglomerates of intestinal loops, cysts and tumors of the pancreas or mesentery etc, • difficulties in defining the point of origin of large lesions, which invade and push aside surrounding structures and organs, as well as intestinal tumors infiltrating the mesentery, • heterogenous, low and high initial contrasting of the lesions with possible presence of calcifications; various types and enhancement intensity; and sometimes no strong enhancement typical for sarcomas, 40