Benign adenomatous kidney neoplasms in children with polycythemia: Imaging findings

PURPOSE: To correlate pathologic, computed tomographic (CT), and ultrasound (US) characteristics of nephrogenic adenofibromas and embryonal adenomas (uncommon pediatric renal tumors) in children. MATERIALS AND METHODS: Medical records and imaging and pathologic findings were reviewed in three children (aged 61/2, 7, and 11 years) with adenomatous renal tumors and polycythemia. Specimens were reviewed at the National Wilms Tumor Study Pathology Center (Loma Linda, Calif). RESULTS: All tumors were smaller than 3 cm in greatest dimension. They were hyperechoic on US scans and had high attenuation on unenhanced CT scans. Two patients underwent nephrectomy for initial diagnosis of Wilms tumor. The third underwent local excision. At pathologic examination, embryonal-appearing adenomatous epithelial cells were found to form tubules and papillae with abundant psammomatous calcifications. Two masses were classified as embryonal adenomas and one as nephrogenic adenofibroma. CONCLUSION: Increased attenuation on CT scans and increased echogenicity on US scans of renal adenomatous tumors are distinctive findings that may reflect the presence of tubulopapillary structures and psammomatous calcifications.