Background: Multiple Endocrine Neoplasia 2B (MEN2B) is characterized by medullary thyroid carcinoma (MTC) before the age of one, pheochromocytoma and several non-endocrine manifestations. Marfanoid habitus is considered to be an important related feature, leading to the assumption that children with MEN2B have a tall stature. However, very little is known about actual growth patterns in children with MEN2B and its implication for final height. Aim: To describe the growth patterns during childhood and adolescence and relate final height to target height (TH) in MEN2B patients. Methods: Growth during childhood was investigated in eight patients with MEN2B under care in a Dutch MEN expertise center. Growth charts were assessed in relation to parental height, age at diagnosis and at thyroidectomy, body mass index (BMI), pubertal development and extensiveness of disease manifestations. Results: Four out of eight patients showed longitudinal growth below their TH range. Three others showed prepubertal growth in the lowest margin of their TH range. Small stature was accompanied by delayed bone maturation. Arm span to height ratio was not increased in any of the (six) patients studied. All four patients who reached adulthood attained final height within their TH range, despite small stature during childhood. Small stature in childhood was not associated with age at diagnosis, age at thyroidectomy, extensiveness of MTC, BMI or endocrine deficiencies. Conclusions: Children with MEN2B did not present with marfanoid features regarding height or arm span. In contrary, short stature may be prevalent, with longitudinal growth beneath the individual TH range. Nevertheless, a normal final height within the TH range may well be reached. Growth patterns seem to be independent of both age at diagnosis and thyroidectomy as well as disease severity.
