Diabetes Mellitus as a Primary Manifestation of Multiple Endocrine Neoplasia Type 2B

A 22-year-old-man presenting with diabetes mellitus was found to suffer from multiple endocrine neoplasia type 213 (MEN B). The characteristic phenotype including mucosal neuromas, musculoskeletal abnormalities and a marfanoid habitus lea us to suspect this diagnosis, which was confirmed by the genetic analysis showing the typical mutation in the RET proto-oncogene at codon 918. Subsequently, diagnoses of bilateral phaeochromocytoma and medullary thyroid carcinoma were made. The patient underwent first a laparoscopic removal of bilateral phaeochromocytoma and a radical thyroidectomy three months later. Both operations were uneventful. After operation, diabetes resolved, an effect partly explainable by an improvement of insulin sensitivity. Thus, clinicians should be aware of a diagnosis of MEN 2B in a young patient presenting with diabetes, a typical phenotype, symptoms of phaeochromocytoma or a nodule in the thyroid.