Multiple endocrine neoplasia type 2b (MEN 2b). Report of 2 pediatric cases.

Two new sporadic cases of multiple endocrine neoplasia type 2b (MEN 2b) are described. Both patients were diagnosed in pediatric age and presented the characteristic features of the syndrome (facies "sui generis", Marfanoid habitus, mucosal neuromas, history of chronic gastrointestinal disturbances) and developed medullary thyroid carcinoma (MTC). In the former case, metastatic neck adenopathies were the first sign by which the disease was recognized. Antitumor treatment consisted of total thyroidectomy, cervical node dissection, administration of I131 and neck irradiation. This patient is alive and well 20 months from diagnosis, still having high serum levels of thyrocalcitonin (TC). In the latter case, the syndrome was diagnosed on clinical grounds before the development of a MTC. The patient was then strictly followed-up and thyroidectomy performed only when serum TC levels rose to abnormally high values: no tumor spread was documented at that time. She is alive and well 4 years from diagnosis.--Early recognition of MEN 2b syndrome is necessary in order to detect and properly treat MTC.