Patients with MEN2B develop MTC and pheochromocytoma and exhibit a recognizable phenotype, characterized by a typical facies, ophthalmologic abnormalities (inability to make tears in infancy, thickened and everted eyelids, mild ptosis, and prominent corneal nerves), skeletal malformations (marfanoid body habitus, narrow long facies, pes cavus, pectus excavatum, high-arched palate, scoliosis, and slipped capital femoral epiphyses), and a generalized ganglioneuromatosis throughout the aerodigestive tract (1). This evidence concerns the gene RET and hereditary pheochromocytoma-paraganglioma.