1. ¹Departments of Pathology and Laboratory Medicine, Indiana University, Indianapolis, IN, USA
2. ²Dipartimento di Patologia, Universitá di Sassari, Sassari, Italy
3. ³Dipartimento di Patologia, Universitá di Verona, Verona, Italy

Correspondence: Dr L Cheng, MD, Departments of Pathology and Laboratory Medicine, Indiana University Medical Center, University Hospital 3465, 550 North University Boulevard, Indianapolis, IN 46202, USA. E-mail: lcheng@iupui.edu

Received 9 January 2006; Revised 6 March 2006; Accepted 10 March 2006; Published online 31 March 2006.

Abstract

End-stage renal disease is associated with an increased incidence of renal cell neoplasms. Among these, recent studies have identified tumors with unusual histological patterns that do not fit into the categories recognized in the current classification system. These tumors often occur in kidneys with acquired cystic disease and are composed mainly of large eosinophilic cells arranged in solid, cribriform, acinar, or papillary patterns. They also contain deposits of calcium oxalate crystals. We investigated three eosinophilic epithelial tumors arising in kidneys with acquired cystic disease from three patients. Each of the tumors was composed of large eosinophilic cells arranged in solid, acinar, or tubulocystic architecture. Deposits of calcium oxalate crystals were present in each tumor. Hale's colloidal stain showed a positive cytoplasmic reaction in one of the neoplasms. Immunohistochemistry displayed positive results for CD10 (3/3), AE1/AE3 (3/3), alpha-methylacyl-CoA racemase (2/3), CAM5.2 (2/3), and vimentin (1/3). Reactions for epithelial membrane antigen, cytokeratin 7, and high molecular weight cytokeratin (34E12) were negative. Fluorescence in situ hybridization analysis showed no losses or gains of chromosomes 1, 2, 6, 10, or 17 in one tumor. There were gains of chromosomes 1, 2, and 6 in two tumors. One of these tumors also showed gains of chromosome 10. Eosinophilic renal cell tumors associated with acquired cystic disease have immunophenotypes and genetic profiles distinct from the renal cell neoplasms recognized in the current classification of renal cell neoplasia, and should be considered as a distinct clinicopathologic entity in the spectrum of renal cell neoplasia.