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Bodard S, Delavaud C, Dariane C, Boudhabhay I, Bensenouci NEI, Timsit MO, Correas JM, Verkarre V, Hélénon O. Low-grade oncocytic tumor of the kidney: imaging features of a novel tumor entity. Abdom Radiol (NY) 2024:10.1007/s00261-024-04487-2. [PMID: 39068611 DOI: 10.1007/s00261-024-04487-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Revised: 06/30/2024] [Accepted: 06/30/2024] [Indexed: 07/30/2024]
Abstract
PURPOSES Low-grade oncocytic tumor (LOT) is a rare renal tumor that has emerged from the spectrum of eosinophilic/oncocytic renal tumors and poses a diagnostic challenge due to its similarity to chromophobe renal cell carcinoma (CHRCC) and renal oncocytoma (RO). The imaging features of this novel tumor entity have not yet been clearly described. The purpose of this study was to describe the imaging features of LOT with radiologic-pathologic correlation. METHODS We conducted a retrospective observational study involving two expert centers. We identified 12 pathologically proven LOT with preoperative imaging available, including at least computed tomography (CT) or magnetic resonance imaging (MRI), from the past 12 years. Three experienced radiologists performed the imaging analysis independently. RESULTS All tumors presented well-defined borders. Nine of the 12 LOT exhibited an early peripheral enhancement with complete or almost complete centripetal fill-in on nephrographic or delayed phases without any particular shape. Three showed a homogeneous contrast enhancement. Macroscopic fat and calcifications were not observed in any of the tumors. CONCLUSION Early peripheral enhancement with complete or almost complete centripetal fill-in on nephrographic or delayed phases without any particular shape suggests a LOT diagnosis. Further analyses involving larger studies are needed to fully confirm these imaging characteristics. To date, a percutaneous biopsy should be performed before considering management.
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Affiliation(s)
- Sylvain Bodard
- Adult Department of Radiology, Service d'Imagerie Adulte, AP-HP-Centre, Hôpital Necker Enfants Malades, Université de Paris Cité, 149 Rue de Sèvres, 75015, Paris, France.
- Laboratoire d'Imagerie Biomédicale, Sorbonne Université, CNRS, INSERM, Paris, France.
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
| | - Christophe Delavaud
- Adult Department of Radiology, Service d'Imagerie Adulte, AP-HP-Centre, Hôpital Necker Enfants Malades, Université de Paris Cité, 149 Rue de Sèvres, 75015, Paris, France
| | - Charles Dariane
- Service d'Urologie, AP-HP-Centre, Hôpital Européen Georges Pompidou, Université de Paris Cité, 75015, Paris, France
| | - Idris Boudhabhay
- Service de Transplantation Rénale, AP-HP-Centre, Hôpital Necker Enfants Malades, Université de Paris Cité, 75015, Paris, France
| | - Nour El Imane Bensenouci
- Service d'Anatomie Pathologie, AP-HP-Centre, Hôpital Européen Georges Pompidou, Université de Paris Cité, 75015, Paris, France
| | - Marc-Olivier Timsit
- Service d'Urologie, AP-HP-Centre, Hôpital Européen Georges Pompidou, Université de Paris Cité, 75015, Paris, France
| | - Jean-Michel Correas
- Adult Department of Radiology, Service d'Imagerie Adulte, AP-HP-Centre, Hôpital Necker Enfants Malades, Université de Paris Cité, 149 Rue de Sèvres, 75015, Paris, France
- Laboratoire d'Imagerie Biomédicale, Sorbonne Université, CNRS, INSERM, Paris, France
| | - Virginie Verkarre
- Service d'Anatomie Pathologie, AP-HP-Centre, Hôpital Européen Georges Pompidou, Université de Paris Cité, 75015, Paris, France
- Equipe INSERM UMR 970 "Genetic and Metabolism of Rare Tumors" Equipe Labélisée Ligue Contre Le Cancer, PARCC, SIRIC CARPEM, Université de Paris-Cité, Paris, France
| | - Olivier Hélénon
- Adult Department of Radiology, Service d'Imagerie Adulte, AP-HP-Centre, Hôpital Necker Enfants Malades, Université de Paris Cité, 149 Rue de Sèvres, 75015, Paris, France
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Do we need an updated classification of oncocytic renal tumors? : Emergence of low-grade oncocytic tumor (LOT) and eosinophilic vacuolated tumor (EVT) as novel renal entities. Mod Pathol 2022; 35:1140-1150. [PMID: 35273336 DOI: 10.1038/s41379-022-01057-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/07/2022] [Accepted: 02/14/2022] [Indexed: 02/07/2023]
Abstract
The category of "oncocytic renal tumors'' includes well-recognized entities, such as renal oncocytoma (RO) and eosinophilic variant of chromophobe renal cell carcinoma (eo-ChRCC), as well as a group of "gray zone" oncocytic tumors, with overlapping features between RO and eo-ChRCC that create ongoing diagnostic and classification problems. These types of renal tumors were designated in the past as "hybrid oncocytoma-chromophobe tumors". In a recent update, the Genitourinary Pathology Society (GUPS) proposed the term "oncocytic renal neoplasm of low malignant potential, not further classified", for such solitary and sporadic, somewhat heterogeneous, but relatively indolent tumors, with equivocal RO/eo-ChRCC features. GUPS also proposed that the term "hybrid oncocytic tumor" be reserved for tumors found in a hereditary setting, typically arising as bilateral and multifocal ones (as in Birt-Hogg-Dubé syndrome). More recent developments in the "gray zone" of oncocytic renal tumors revealed that potentially distinct entities may have been "hidden" in this group. Recent studies distinguished two new entities: "Eosinophilic Vacuolated Tumor" (EVT) and "Low-grade Oncocytic Tumor" (LOT). The rapidly accumulated evidence on EVT and LOT has validated the initial findings and has expanded the knowledge on these entities. Both are uniformly benign and are typically found in a sporadic setting, but rarely can be found in patients with tuberous sclerosis complex. Both have readily distinguishable morphologic and immunohistochemical features that separate them from similar renal tumors, without a need for detailed molecular studies. These tumors very frequently harbor TSC/MTOR mutations that are however neither specific nor restricted to these two entities. In this review, we outline a proposal for a working framework on how to classify such low-grade oncocytic renal tumors. We believe that such framework will facilitate their handling in practice and will stimulate further discussions and studies to fully elucidate their spectrum.
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TSC/mTOR Pathway Mutation Associated Eosinophilic/Oncocytic Renal Neoplasms: A Heterogeneous Group of Tumors with Distinct Morphology, Immunohistochemical Profile, and Similar Genetic Background. Biomedicines 2022; 10:biomedicines10020322. [PMID: 35203531 PMCID: PMC8869370 DOI: 10.3390/biomedicines10020322] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/23/2022] [Accepted: 01/27/2022] [Indexed: 02/01/2023] Open
Abstract
A number of recently described renal tumor entities share an eosinophilic/oncocytic morphology, somewhat solid architectural growth pattern, and tendency to present as low-stage tumors. The vast majority of such tumors follow a non-aggressive clinical behavior. In this review, we discuss the morphological, immunohistochemical, and molecular genetic profiles of the three most recent novel/emerging renal entities associated with TSC/mTOR pathway mutations. These are eosinophilic solid and cystic renal cell carcinoma, eosinophilic vacuolated tumors, and low-grade oncocytic tumors, which belong to a heterogeneous group of renal tumors, demonstrating mostly solid architecture, eosinophilic/oncocytic cytoplasm, and overlapping morphological and immunohistochemical features between renal oncocytoma and chromophobe renal cell carcinoma. All three tumors also share a molecular genetic background with mutations in the mTORC1 pathway (TSC1/TSC2/mTOR/RHEB). Despite the common genetic background, it appears that the tumors with TSC/mTOR mutations represent a diverse group of distinct renal neoplasms.
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