Forty-one cases of mesenteric and omental cysts are reported. Histologically, several specific types could be distinguished: lymphangioma, 19 cases; nonpancreatic pseudocyst, 11 cases; enteric duplication cyst, six cases; mesothelial cyst, three cases; and enteric cyst, two cases. A lymphangioma is usually a multiloculated cyst located in the mesentery that shows no discernible wall on computed tomography (CT) and may have characteristics of fat on CT and magnetic resonance imaging. Abnormalities in the small bowel mucosa were frequently noted on barium studies. A nonpancreatic pseudocyst is usually a unilocular or multilocular cyst located in either the mesentery or the omentum, with abundant debris sonographically and an enhancing wall on CT. An enteric duplication cyst is a unilocular cyst with an enhancing wall on CT. Mesothelial and enteric cysts are anechoic, thin-walled cysts. Emphasis is placed on the importance of identifying lymphangioma, which is more difficult to manage than the other forms of mesenteric and omental cysts.

Seventeen proved cases of intrahepatic cholangiocarcinoma (ICAC) were reviewed to establish a radiologic-pathologic correlation. The most common appearance of ICAC at computed tomography (CT) is that of a single, homogeneous low-attenuation mass. Multiple low-attenuation lesions were present in four cases. Calcification was depicted by CT in three cases. At angiography, ICAC has a variable appearance with avascular, hypovascular, and hypervascular patterns possible. Portal obstruction was seen in only one case. The most common appearance of ICAC at sonography is that of a homogeneously hyperechoic mass, either single or multiple. In only one case was ICAC hypoechoic. Plain abdominal radiography demonstrated calcification in three patients and evidence of Thorotrast (thorium dioxide) deposition in one. Upper gastrointestinal series demonstrated abnormal gastric folds in two cases, corresponding to gastric invasion by ICAC. There were no characteristic radiographic findings, but the following features may be helpful in differentiating ICAC from other primary intrahepatic tumors, particularly typical hepatocellular carcinoma: a homogeneously echogenic or high-attenuation appearance on images that reflects the uniform nature observed at pathologic examination, the presence of calcification, and the uncommon invasion of portal or hepatic veins. Conversely, the presence of satellite lesions may blur the the distinction between ICAC and metastatic liver disease.

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[5, 6]. This series demonstrates the spectrum of radiologic findings and provides new evidence as to the pathogenesis of false cysts. Materials and MethodsFor 52 cases of nonneoplastic, nonparasitic splenic cysts with radiographs in the files of the Registry of Radiologic Pathology at the AFIP, clinical data were derived from summaries submitted by the case contributors.All diagnoses were confirmed by review of both gross and histologic data by the Department of Hematologic Pathology. The cysts were categorized as either "true' or "false.

Gastrointestinal teratomas are uncommon, benign neoplasms that occur primarily in children. A retrospective review of five cases (two gastric, one pancreatic, one mesenteric, and one in the lesser omentum) is presented with emphasis on the computed tomographic and ultrasonographic appearances. Principal findings are a well-defined mass with separate cystic and solid components of varying proportions, discrete areas with densities similar to that of fat, or coarse, globular calcifications within the solid component. Recognition of these findings may allow the radiologist to make a correct preoperative diagnosis of teratoma.