Histological and immunohistochemical reassessment of surgical specimens of oncocytic renal neoplasms for reclassification, according to the 5th edition of the IARC/WHO publication of genitourinary tumors, also considering provisional entities.

• Grant number: 22/16907-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2023
• End date: April 30, 2024
• Field of knowledge: Health Sciences - Medicine - Pathological Anatomy and Clinical Pathology
• Principal Investigator: Kátia Ramos Moreira Leite
• Grantee: Henrique Laurent Lepine
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Kidney tumors with oncocytic features encompass widely known entities, such as oncocytomas and chromophobe carcinomas, as well as a variety of subtypes with mid-ground characteristics, formerly called "hybrid oncocytoma-chromophobe tumors". Recently, however, the publication of the 5th edition of the IARC/WHO book established new entities for the classification of this "intermediate zone" of oncocytic tumors, namely: renal oncocytic neoplasm with low malignant potential, hybrid oncocytic renal tumor associated with Birt-Hogg-Dube tumor (HOCT), vacuolated eosinophilic tumor (EVT) and low-grade oncocytic tumor (LOT).Other "molecularly defined" tumors, with a more aggressive pattern are also part of the differential diagnosis, such as RCC deficient in succinate dehydrogenase and RCC deficient in fumarate hydratase. In addition to other rarer differentials such as epithelioid angiomyolipoma.Thus, considering the histological, immunohistochemical and sometimes prognostic differences, we aimed to reclassify the samples from the Genoa/LPCM laboratory according to the new criteria. For this, Hematoxylin&Eosin slides will be re-evaluated and the most representative block will be chosen for construction of the "tissue microarray", followed by the use of specific antibodies for the immunohistochemistry technique. After reviewing the slides and the results of the immunohistochemistry, we sought confirmation of the initial diagnosis or reclassification of the neoplasm.