Renal Tumors with Oncocytic and Papillary Features: A Phenotypic and Genotypic Study.

Tania Franceschini,Michelangelo Fiorentino,Francesca Giunchi,Elisa Capizzi,Veronica Mollica,Mattia Banfi,Riccardo Schiavina,Annalisa Altimari,Francesco Massari

doi:10.3390/diagnostics11020184

Tania Franceschini, Michelangelo Fiorentino + Show 7 more

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https://doi.org/10.3390/diagnostics11020184

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Abstract

The occurrence of kidney oncocytic lesions with an admixed papillary component is not unusual in routine pathology practice. These neoplasms with dual morphology are classically recognized as collision tumors with variable malignant potential. Using immunohistochemistry, we investigated fluorescent in situ hybridization and next generation sequencing of the genetic and phenotypic profiles in the two components of 11 kidney tumors with colliding oncocytic and papillary features. The oncocytic component was CD117 positive, CK7 negative, and AMACR negative; the papillary component was CK7 positive, AMACR positive, and CD117 negative in all cases. Fluorescence in situ hybridization (FISH) results were inconsistent. Next generation sequencing (NGS) analysis demonstrated that the mutations identified in the two tumor components were identical and displayed an allelic frequency of approximately 50%, strongly suspicious for genetic polymorphisms. The two oncocytic and papillary tumor counterparts shared the same genetic profile and did not harbor pathogenic mutations. Clinical confirmation of the biological benign features of these tumors is required. The term collision tumor is not suitable for these neoplasms, and we propose the term oncopapillary tumor for this histological entity.

Highlights

The number of histological new entities among renal cell tumors is steadily increasing over the years [1]
Eosinophilic renal neoplasms comprise a spectrum of tumors ranging from the benign oncocytoma to the indolent Hybrid Oncocytic Tumor (HOT) until the frankly malignant Chromophobe Renal Cell Carcinoma (ChRCC) [2,3]
Collision tumors imply the coexistence of two discrete histogenetically and genetically distinct cell types arising from a common source.A recent study reported the immunohistochemical (IHC) and the fluorescence in situ hybridization (FISH) characteristics of 17 tumors of the kidney with a papillary component admixed with another histotype [7]

Summary

Introduction

The number of histological new entities among renal cell tumors is steadily increasing over the years [1] This new landscape of renal cell tumors includes several lesions with eosinophilic or oncocytic histology. Collision tumors imply the coexistence of two discrete histogenetically and genetically distinct cell types arising from a common source.A recent study reported the immunohistochemical (IHC) and the fluorescence in situ hybridization (FISH) characteristics of 17 tumors of the kidney with a papillary component admixed with another histotype [7]. Most neoplasms in this study were papillary renal cell proliferations arising in the background of oncocytoma and chRCC, and the two components showed distinct ICH and FISH features, confirming the collision nature of the tumors [7]. The recognition of the malignant histology of at least one component leads to the classification of the collision tumor as malignant with clinical and follow-up consequences

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