FLCN and oncocytic adenoma: Folliculin (FLCN) is a tumor suppressor gene that is deficient in Birt-Hogg-Dube syndrome (BHD), a disorder that features renal carcinoma of multiple histological types including hybrid oncocytic RCC, chromophobe RCC, oncocytoma, multiple and bilateral clear cell RCC (Verine et al., 2010).