Multiple Endocrine Neoplasia Type 2B: Early Diagnosis by Multiple Mucosal Neuroma and Its DNA Analysis.

Multiple endocrine neoplasia type 2B (MEN 2B) is a rare disease caused by germline mutations in the RET proto-oncogene and is transmitted in an autosomal dominant fashion. It is characterized by medullary thyroid carcinoma, pheochromocytoma and mucosal neuroma developing in the tongue, lip, intestinal tract, palate etc. Among these neoplasias, mucosal neuroma generally develops from early childhood. Therefore, early detection and proper treatment can minimize the disease course. Here we describe a 9-year-old male who presented with multiple verrucous papules and nodules on his lips, tongue and gingiva that were there since birth. Histologic findings of his lips and tongue showed well-defined nerve bundles and DNA analysis revealed a M918T mutation at codon 918 of the RET oncogene. He was diagnosed early as having MEN 2B according to his genetic and phenotypic features.