(MEN3) (mŭl'ti-pĕl en'dō-krin nē-ō-plā'zē-ă) Syndrome characterized by tumors found in MEN2, tall, thin habitus, prominent lips, and neuromas of the tongue and eyelids; autosomal dominant inheritance, caused by mutation in the RET oncogene on 10q. Synonym(s): multiple endocrine neoplasia 2B.