The penetrance of MEN2 pheochromocytoma is not only determined byRETmutations

Multiple endocrine neoplasia type 2 (MEN2) is a rare syndrome subdivided into 2 main entities: MEN2A and MEN2B (Donis-Keller et al. 1993, Mulligan et al. 1993, Eng et al. 1996). Genetic results can predict the natural history of medullary thyroid carcinoma (MTC) depending on the mutation of RET. This is the basis for ATA guidelines giving different ages to perform early thyroidectomy in such patients (Wells et al. 2015). MEN2A and MEN2B are also characterized by the occurrence of pheochromocytoma (PHEO), though less frequent than MTC. PHEO is a chromaffin tumor arising from the medullar zone of the adrenals and responsible for mortality if left undiagnosed (Lenders et al. 2005). Precise comparative large-scale epidemiological data on PHEO penetrance in different geographical zones are however missing in the literature as the majority of published studies were coming from a single Center or a single country.