This variability may be attributed to several factors: our institution’s tertiary referral status could introduce selection bias through complex case concentration; the diagnostic challenge posed by the tumor’s indolent progression of the tumour, and the confounding effect of undiagnosed VHL disease in presumed sporadic cases (39% of sporadic ELSTs harbor germline VHL mutations [23]). This evidence concerns the gene VHL and von Hippel-Lindau disease.