The occurrence of multiple endocrine neoplasia type IIb, in two children of an affected mother.

Two children with multiple endocrine neoplasia syndrome, Type IIb, (MEN IIb), whose natural mother died from complications of general anesthesia, due to undiagnosed bilateral pheochromocytomas, are described. Of particular interest is the fact that the daughter presented with many stigmata of the syndrome, including the typical facies, while her brother had no obvious clinical manifestations of the syndrome. Both children to date have undergone total thyroidectomy, and pathology reports have confirmed the presence of medullary thyroid carcinoma.