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Case Reports in Pathology
Volume 2013, Article ID 675875, 5 pages
Case Report

Adult Nephroblastoma with Predominant Epithelial Component: A Differential Diagnostic Candidate of Papillary Renal Cell Carcinoma and Metanephric Adenoma—Report of Three Cases

1Departments of Diagnostic Pathology, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
2Divisions of Surgical Pathology, Sendai City Hospital, Sendai 984-8501, Japan
3Department of Pathology, Saitama Medical University International Medical Center, Saitama 350-1298, Japan
4Department of Human Pathology, Wakayama Prefectural Medical College, Wakayama 641-8509, Japan
5Department of Urology, Chiba University Graduate School of Medicine, Chiba 260-8670, Japan
6Division of Diagnostic Pathology, Keio University Hospital, Tokyo 160-8582, Japan
7Division of Diagnostic Pathology, Kochi Red Cross Hospital, Kochi 780-8562, Japan
8Department of Molecular Pathology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan

Received 4 July 2013; Accepted 30 July 2013

Academic Editors: K. Aozasa, H. Kuwabara, and M. M. Picken

Copyright © 2013 Shiho Watanabe et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Although nephroblastoma is the commonest renal tumor of childhood, it is rare in adults. In cases of predominantly epithelial type occurring in adulthood, it might be difficult to distinguish it from papillary renal cell carcinoma and metanephric adenoma. Here, we report three cases of adult epithelial nephroblastoma in 24-, 76-, and 21-year-old females. Histologically, the tumors were composed of papillotubular architectures of small and uniform tumor cells with high nucleocytoplasmic ratio without blastemal element. Immunohistochemically, the tumor cells were positive for WT-1 and CD57 but negative for AMACR, which was helpful to exclude the possibility of papillary renal cell carcinoma. Metanephric adenoma is a benign tumor, which can be distinguished by the observation of the cellular atypism and growth pattern. However, nephroblastoma with predominant epithelial element mimics the malignant counterpart of metanephric adenoma, that is, “metanephric adenocarcinoma.”