Axonal neuropathy, long limbs and bumpy tongue: Think of MEN2B

Abstract

Multiple endocrine neoplasia type 2 (MEN 2) is an uncommon autosomal dominant cancer syndrome which can be associated with nerve conduction abnormalities. A 14-year-old boy with a family history of consanguinity developed progressive gait clumsiness, pes cavus, hypotonia, and mucosal tumors of the lips and tongue since the age of 3 years. At age 11 years, he was diagnosed with an hereditary motor neuropathy (Charcot-Marie-Tooth syndrome). Physical examination revealed a Marfanoid habitus, mucocutaneous verrucous tumors, thyroid nodules, and cervical adenopathy. Genetic testing demonstrated the p.M918T mutation in the RET gene, and blood tests showed elevated levels of calcitonin. Clinical suspicion in MEN2 is crucial for early diagnosis and subsequent therapy. Mucosal neuroma and a Marfanoid habitus are especially useful. Other neurologic manifestations should not disguise the endocrine disorder, because early diagnosis and treatment of medullary thyroid carcinoma determines the prognosis.