MEN2B, the most aggressive subtype of MEN, is characterised by early-onset MTC, pheochromocytoma, and suggestive extra-endocrine features: distinctive faces (neuromas of the lips and tongue, prominent lips), ophthalmologic abnormalities (alacrima, thickened and everted eyelids, mild ptosis, and medullated corneal nerve fibres), skeletal anomalies (marfanoid habitus, pectus excavatum, scoliosis, pes cavus, joint laxity), and ganglioneuromatosis of the gastrointestinal tract [101]. This evidence concerns the gene RET and pheochromocytoma.