Advances in renal neoplasia: recommendations from the 2012 International Society of Urological Pathology Consensus Conference.

The International Society of Urological Pathology (ISUP) 2012 Consensus Conference made recommendations regarding the classification, prognostic factors, staging, and immunohistochemical and molecular assessment of adult renal tumors. There was consensus that 5 entities should be recognized as novel tumors: tubulocystic renal cell carcinoma (RCC), acquired cystic disease-associated RCC, clear cell papillary RCC, microphthalmia transcription factor-family translocation RCC [in particular t(6; 11) RCC], and hereditary leiomyomatosis RCC syndrome-associated RCC. In addition, 3 rare epithelial carcinomas were considered emerging or provisional entities: thyroid-like follicular RCC, succinate dehydrogenase B deficiency-associated RCC, and anaplastic lymphoma kinase translocation RCC. There were also a number of suggested modifications to existing World Health Organization 2004 categories, with the new classification to be known as the ISUP Vancouver Classification. Tumor morphotype, sarcomatoid/rhabdoid differentiation, and tumor necrosis were identified as significant prognostic parameters for RCC. The ISUP Grading System was accepted with grades 1-3 of clear cell and papillary RCC being based on nucleolar prominence, whereas extreme nuclear pleomorphism or sarcomatoid and/or rhabdoid differentiation defined grade 4 tumors. It was agreed that chromophobe RCC should not be graded. Consensus guidelines were formulated for specimen handling, and it was agreed that renal sinus invasion is present when tumor is in direct contact with fat or loose connective tissue of the sinus or if there is involvement of endothelial-lined spaces within the renal sinus, regardless of the size. The role of biomarkers in the diagnosis and assessment of prognosis of renal tumors was considered, and panels of immunohistochemical markers were identified for use in specific differential diagnostic scenarios.