The 2016 World Health Organization Renal Tumor Classification defines renal oncocytoma (RO) as a benign epithelial tumor; however, malignant histopathologic features have been documented. Rare cases with metastases have been reported. We describe the case of a 62-year-old woman who was referred to the Urology Clinic for a routine work-up. Magnetic resonance imaging and computerized tomography showed a 7-cm mass in the middle and lower portions of the left kidney and 2 suspected liver metastases. The patient underwent surgery. Microscopically both renal and liver lesions presented solid, solid-nested, and microcystic architecture, composed predominantly of large eosinophilic cells without any worrisome pattern except the vascular extension. The cells were positive for S100A1, CD117, and PAX-8 and negative for CAIX, CK7, and AMACR. Fluorescence in situ hybridization showed a disomic profile for the chromosomes 1, 2, 6, 7, 10, 17. No mutation of coding sequence of the SDHB, SDHC, SDHD, VHL, and BHD genes and no loss of heterozygosity at 3p were found. The final diagnosis was “RO” according to the 2016 World Health Organization Renal Tumor Classification with “liver metastases.” This report provides a wide clinical-pathologic, immunophenotypical and molecular documentation of a RO with liver metastases.
Departments of †Diagnostics and Public Health
‡General Surgery and Odontoiatrics
#Medicine, Renal Unit, University and Hospital Trust, Verona
∥Department of Specialised, Experimental and Diagnostic Medicine, Sant’Orsola-Malpighi University Hospital, Bologna
¶Anatomic Pathology, Pederzoli Hospital, Peschiera Del Garda, Italy
§Department of Pathology, Faculty of Medicine in Plzen, Charles University, Pilsen, Czech Republic
This study did not receive any funding from the National Institutes of Health (NIH), the Wellcome Trust, and the Howard Hughes Medical Institute (HHNI).
Internal funding from the Department of Diagnostics and Public Health (M.B., G.M., Funded University Research 2015) has been used in part for study-related facilities.
The authors declare no conflict of interest.
Reprints: Matteo Brunelli, MD, PhD, Department of Diagnostics and Public Health, University and Hospital Trust of Verona, P.le L. Scuro n. 10, Verona 37134, Italy (e-mail: firstname.lastname@example.org).
Received November 17, 2016
Accepted November 18, 2016