A female patient with a solitary functioning nodule of the thyroid was operated upon. She had clinical symptoms of thyrotoxicosis and the thyroid scintigram showed a “hot” nodule corresponding to the palpable nodule. A cold area was noted in the “hot” nodule. At operation, a 1.6 by 2cm papillary carcinoma was found to be embedded within a functioning follicular adenoma, and metastatic foci were detected histologically in the ipsilateral paratracheal lymph nodes.