Pancreatoblastoma: imaging findings in 10 patients and review of the literature.

PURPOSE: To describe the features of pancreatoblastoma at magnetic resonance (MR) imaging, computed tomography (CT), and ultrasonography (US). MATERIALS AND METHODS: Imaging and surgical findings in 10 patients (age range, 2-20 years; mean age, 6.8 years) with pathologically proved pancreatoblastoma were reviewed for tumor size, organ of origin, definition and quality of tumor margins, tumor heterogeneity, calcification, enhancement, ascites, biliary and/or pancreatic ductal dilatation, local invasion, adenopathy, vascular invasion, vascular encasement, metastases, and signal intensity on MR images. Results from 10 CT, seven US, and three MR imaging examinations were reviewed. RESULTS: Five of the 10 tumors were pancreatic; four others appeared to be pancreatic or hepatic. Most had well-defined margins (nine of 10), were heterogeneous (nine of 10), and enhanced (10 of 10). Other findings included calcification (two of 10), biliary and pancreatic ductal dilatation (one of 10), and ascites (three of 10). Hepatic (two patients) and pelvic (two patients) metastases were present. Adenopathy (two patients) and vascular invasion (one patient) were not identified radiologically. Tumors had low to intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. CONCLUSION: Pancreatoblastoma is typically a heterogeneous tumor with well-defined margins that may appear to arise from the pancreas or liver. It may behave aggressively, with localized vascular or bowel invasion or with widespread metastatic disease. Although it is rare, it should be considered in the differential diagnosis of an upper abdominal mass in a child.

Perforation of multiple gastric duplication cysts: diagnosis by sonography.

A case of perforation of multiple gastric duplication cysts is presented. The rarity of this case is based on its multiplicity, its small size, its perforation into peritoneal cavity, as well as on the detection of tiny foci of ectopic pancreatic tissue at the site of perforation. The sonographic appearance and the clinical manifestations are discussed.

Bladder distention and pyelectasis in the male fetus: causes, comparisons, and contrasts.

The objective of this paper was to determine if prenatal sonographic findings can accurately differentiate between the causes of bladder distention and pyelectasis in the male fetus. Twenty-one cases were evaluated for the presence of oligohydramnios, posterior urethral dilation, bladder wall thickening, urachal patency, cortical thinning, cortical cysts, and increased renal echogenicity. Postnatal diagnosis included posterior urethral valves (10 cases), prune belly syndrome (four cases), vesicoureteral reflux (four cases), left ureterovesical junction obstruction (one case), and nonrefluxing, nonobstructive megacystis-megaureter (two cases). Oligohydramnios was present in eight of 10 cases of posterior urethral valves and in one of four cases of prune belly syndrome. A dilated posterior urethra was noted in seven of 10 cases of posterior urethral valves and transiently in two of four cases of prune belly syndrome. Bladder wall thickening developed in all cases of posterior urethral valves and was noted in two of four patients with prune belly syndrome. A patent urachus likewise was identified in two of four cases of prune belly syndrome. The presence of oligohydramnios, progressive bladder wall thickening, and dilated posterior urethra was most suggestive of posterior urethral valves, whereas the presence of a patent urachus was most suggestive of prune belly syndrome. The presence of pyelectasis and megacystis without additional amniotic fluid, bladder, urethral, or renal abnormalities was most suggestive of vesicoureteral reflux, ureterovesical junction obstruction, or nonrefluxing, nonobstructive megacystis-megaureter. Owing to the overlap and evolution of these findings, close follow-up evaluation is recommended.

Nephrogenic rests, nephroblastomatosis, and associated lesions of the kidney.

The fetal kidney is formed by the development of nephrons from fetal metanephric blastema surrounding the ureteric bud. The fetal renal tissue matures into normal renal parenchyma during gestation, but, occasionally, fetal tissue persists into infancy as microscopic foci called nephrogenic rests. Nephrogenic rests are found in approximately 1% of infant kidneys at autopsy. Nephrogenic rests are associated with an increased risk of Wilms tumor, and it is theorized that nephrogenic rests undergo neoplastic change into Wilms tumor. Fortunately, this transformation occurs in less than 1% of young children with nephrogenic rests. Nephrogenic rests are associated with many syndromes, including Beckwith-Wiedemann syndrome, hemihypertrophy, and sporadic aniridia. Children with identifiable syndromes, once diagnosed, should be screened for the development of Wilms tumor. Nephrogenic rests are associated with other lesions such as multilocular cystic nephroma and multicystic dysplasia, usually without malignant complications.

Prenatal diagnosis of glomerulocystic kidney disease in short-rib polydactyly syndrome type II, Majewski type.

An 18-year-old gravida 1 para 0 female was presented at 35 weeks' gestation with severe oligohydramnios. Sonography revealed a fetus with hydrops, bilaterally enlarged echogenic kidneys, and short extremities. The infant died at birth and autopsy was compatible with short-rib polydactyly syndrome type II, Majewski type. Renal histology was consistent with glomerulocystic disease.