Kidney cancers are among the 10 most common tumors in men and women with a high risk of death: 50% of patients with a kidney cancer will develop metastases during the outcome.
Over the years, histologic classifications have changed, but the histologic subtypes, the grading and staging of such tumors have predictive significance for therapeutic approaches. Moreover, some new entities to be characterized, require a histologic, an immunohistochemistry and also a molecular analysis.
Kidney cancers are confronted with different problems when analyzing a biopsy or surgical specimen : subtyping the renal cell carcinomas among the 14 histologic subtypes, recognizing rare kidney cancers especially those which need a molecular analysis, differentiating benign to malignant kidney tumors.
In the French Network of rare kidney cancers (Carare, French National institute of Cancer/INCa), we noted a reported rates of diagnostic discrepancies around 30%.
Inappropriate pathological diagnosis may led to an inappropriate management that may affect therapeutic strategy.
A second opinion is thus necessary when the referring pathologist is uncertain of his/her diagnosis or if the patient or his/her doctor wants a second opinion.
The main questions on kidney cancers are :