Fumaratehydratase-deficient renal cell carcinoma: a clinicopathological and molecular study of 13 cases.

FH-deficient RCC is a rare renal tumour and has a wide morphological spectrum. Most of the tumours had high-grade nuclei and were aggressive. However, we observed a morphological subtype of FH-deficient RCC with low-grade nuclei and eosinophilic cytoplasm, which might mainly occur in young women and show a relatively good prognosis.