MULTIPLE IDIOPATHIC MUCOSAL NEUROMAS - A MINOR FORM OF MULTIPLE ENDOCRINE NEOPLASIA TYPE 2B OR A NEW ENTITY

Multiple endocrine neoplasia type 2B (MEN 2B) is a rare autosomal domi nant process characterized by medullary thyroid carcinoma, pheochromoc ytoma, and mucosal neuromas. A point mutation at codon 918 of the RET protooncogene has been observed in approximately 90% of patients and f amilies with MEN 2B. Mucosal neuromas are the most consistent and dist inctive feature (100% of patients) of MEN 2B and are considered pathog nomonic. We describe a 35-year-old woman with mucosal neuromas of the lower lip and tongue that appeared in early childhood. Examination did not reveal other abnormalities. After a follow-up of more than 22 yea rs with periodic clinical, biochemical, and radiologic studies, no evi dence of MEN 2B has been detected. Analysis of the RET protooncogene e xons 10, 11, and 16 did not demonstrate point mutation in the MEN 2B r egion (M918T).