Multiple endocrine neoplasia type IIb: a clinicopathological report

The clinicopathological findings in a 12-year-old boy with multiple endocrine neoplasia type IIb (MEN-IIb) are presented. He demonstrated the characteristics of a Marfanoid habitus and had mucosal neuromas of the lips, tongue, eyelids, and cornea. The enlarged right thyroid lobe showed an increased thallium-201 chloride uptake, and the serum calcitonin level was markedly raised. A total thyroidectomy was performed. Histopathological examination showed an infiltrating medullary carcinoma of the thyroid (MCT) and metastatic spread to supraclavicular lymph nodes. Special stains, immunocytochemistry, and electron microscopy revealed mucin-containing follicular structures lined by calcitonin-positive and thyroglobulin-negative tumour cells. Ultrastructurally the mucosal neuromas consisted of proliferating perineurial and Schwann cells. The serum calcitonin level fell below 300 pmol/L, and his stools returned to normal postoperatively. Because the incidence of MCT in MEN-IIb is virtually 100%, a total thyroidectomy in high risk patients--even before clinical evidence of malignant tumours--may be the only hope of cure.