Fumarate Hydratase–deficient Renal Cell Carcinoma Is Strongly Correlated With Fumarate Hydratase Mutation and Hereditary Leiomyomatosis and Renal Cell Carcinoma Syndrome

Hereditary leiomyomatosis and renal cell carcinoma syndrome-associated renal cell carcinomas (RCC) are difficult to diagnose prospectively. We used immunohistochemistry (IHC) to identify fumarate hydratase (FH)-deficient tumors (defined as FH negative, 2-succinocysteine [2SC] positive) in cases diagnosed as "unclassified RCC, high grade or with papillary pattern," or "papillary RCC type 2," from multiple institutions. A total of 124 tumors …