Renal oncocytoma: a comparative clinicopathologic study and fluorescent in-situ hybridization analysis of 73 cases with long-term follow-up

Marie Dvorakova,Tracy L Mercuri,Rajiv Dhir,Marie B Acquafondata,Carol R Sherer,Sheldon I Bastacky,Kathleen M Cieply,Anil V Parwani

doi:10.1186/1746-1596-5-32

Marie Dvorakova, Tracy L Mercuri + Show 6 more

Open Access

https://doi.org/10.1186/1746-1596-5-32

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Abstract

Clinical studies have confirmed that renal oncocytoma (RO) is a benign neoplasm with excellent prognosis. In diagnostically challenging cases of renal oncocytic epithelial neoplasms, fluorescent in-situ hybridization (FISH) is increasingly being used and its ability to distinguish RO from chromophobe renal cell carcinoma (ChRCC) has been documented. In this study, we evaluated the differential diagnostic contribution of FISH in cases of RO.Clinicopathologic data and glass slides from 73 patients with RO were reviewed; 20 cases of ChRCC were included for comparison. FISH analysis of formalin-fixed, paraffin-embedded sections was performed using centromeric probes for chromosomes 1, 2, 7 and 17. FISH analysis revealed ROs had frequent loss of signal for chromosome 1 (56%) and 17 (44%). Tumors with more than one loss were common (41%) and 10% cases showed loss of all chromosomes examined. A total of 18% cases did not show any abnormality.Our study shows that chromosomal abnormalities in both ROs and ChRCCs are common with frequent loss of chromosomes 1 and 17. No association was found between overall patient survival and the extent of chromosomal abnormalities. FISH results, even those showing significant chromosomal abnormalities, should not alter the primarily morphology-based diagnosis of RO.

Highlights

Renal oncocytomas (ROs) comprise approximately 3-7% of renal epithelial neoplasms [1,2,3]
To the renal oncocytoma group, none of the patients with available follow-up died of disease or developed metastases
Renal oncocytomas are relatively uncommon neoplasms accounting for 3-7% of primary renal epithelial neoplasms [1,2,3]

Summary

Introduction

Renal oncocytomas (ROs) comprise approximately 3-7% of renal epithelial neoplasms [1,2,3]. Common origin of RO and chromophobe renal cell carcinoma (ChRCC) from the intercalated cells of collecting ducts explains the histomorphologic, immunophenotypical, ultrastructural and molecular similarities of both neoplasms [2,3,4,5,6,7]. Molecular and fluorescent in-situ hybridization (FISH) studies of ROs described partial or total loss of chromosome 1 to be the most consistently reported clonal chromosomal abnormality in RO [11,12,13] with a possible tumor suppressor gene expected on chromosome 1p [14]. FISH was considered to be a potentially useful tool for distinguishing RO from ChRCC, with the former showing no abnormality or loss

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