Renal metanephric adenoma (MA) is an extremely rare benign tumor, especially in children under the age of 12 years old. In this article, we report a case of MA that was incidentally discovered in a 2-year-old girl by ultrasound. Magnetic resonance scan revealed a mass of right kidney that was hypointense and hyperintense on T1- and T2-weighted images, respectively. Laparoscopic nephron-sparing surgery was carried out to remove the lesion. Histopathologic examination of the specimen revealed MA with clear surgical margins. Immunohistochemically, the tumor cells showed focal reactivity for CD56, pan-cytokeratin (AE1/AE3), and epithelial membrane antigen, and negative reactivity for Wilms' tumor 1 gene product. Meanwhile, the tumor stroma was diffusely positive for vimentin. We also review the literature regarding the clinical, imaging, and histopathologic features of this lesion in the pediatric population.
Departments of *Pediatric Surgery
‡Radiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
Supported by the National Natural Science Foundation of China (No. 30200284, No. 30600278, No. 30772359), Program for New Century Excellent Talents in University (NCET-06-0641), and Scientific Research Foundation for the Returned Overseas Chinese Scholars (2008–889).
Reprints: Qiangsong Tong, PhD, MD, Department of Pediatric Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, P. R. China (e-mail: firstname.lastname@example.org).
Received for publication January 5, 2010; accepted March 26, 2010
Hong Mei and Liduan Zheng contributed equally to this work.