Background: Multiple endocrine neoplasia (MEN) type IIb is an autosomal dominantly inherited disorder associated with medullary thyroid cancer, pheochromocytoma, and a characteristic phenotype. The present study was performed to investigate the natural course of the syndrome and to describe its expression.
Methods: The medical records of 18 patients with MEN IIb, seven male and 11 female, were reviewed.
Results: The mean age at diagnosis of MEN IIb was 18 years (range, 8 to 41 years). All 18 patients had medullary thyroid cancer. In three patients, medullary thyroid cancer was diagnosed via screening. In two of these patients, the calcitonin value normalized after thyroidectomy. One patient died of metastases from medullary thyroid cancer at the age of 20 years (median duration of follow-up, 10 years). Eight of the 18 patients had pheochromocytomas. All of our patients had neuromas and bumpy lips, and all but one had a marfanoid habitus. A large proportion of the patients had intestinal abnormalities (75%), thickened corneal nerves (69%), skeletal abnormalities (87%), and delayed puberty (43%).
Conclusions: The course of medullary thyroid cancer in MEN IIb is not always as aggressive as is generally thought. Periodic examination of relatives who are at risk may lead to early diagnosis and curative treatment. Intestinal abnormalities, skeletal abnormalities, and delayed puberty are commonly found in association with MEN IIb.