Of note, high‐grade and sarcomatoid change in SDH‐deficient RCCs may be either focal or diffuse, resulting in ‘unclassifiable RCC’ morphology, which justifies a low threshold for IHC screening in any difficult‐to‐classify eosinophilic high‐grade renal tumour, particularly found in a younger adult.64, 69. Here, SDHB is linked to renal cell carcinoma.