Papillary thyroid carcinoma in Danish patients with familial adenomatous polyposis.

All patients from the nationwide Danish Polyposis Register have been followed up with regard to thyroid carcinoma. During the period 1943–1985, 2/107 Danish women and 0/138 men developed papillary thyroid carcinoma after the diagnosis of familial adenomatous polyposis. The expected number among females was 0.02 resulting in an observed/expected ratio of 100 (95% confidence limits 12–361). Consequently, thyroid carcinoma should be included among the extracolonic lesions, which may develop in any female polyposis patient. However, regular thyroid examination is not indicated, as thyroid carcinoma is uncommon and as the prognosis is excellent.