Multiple endocrine neoplasia type 2b with a good prognosis.

Three patients with the multiple endocrine neoplasia syndrome type 2b (MEN 2b) and a good prognosis are described. During a follow-up period of 41 to 84 months, only little progression of metastases of medullary carcinoma of the thyroid was observed. In one of the patients, liver metastases of medullary carcinoma of the thyroid were already present in biopsy specimens taken 22 years earlier. In two patients bilateral pheochromocytomas were completely removed. These observations show that, in contrast to the general view, the clinical course of MEN 2b can be as indolent as that of MEN 2a or sporadic forms of the tumors involved, despite the presence of metastases. This may indicate that factors other than the type of inheritance contribute to the outcome of the disease.