The association of differentiated thyroid cancer and a functioning nodule is very low. We report on a case of papillary carcinoma in an autonomously functioning thyroid nodule in a 39 year-old female patient. The nodule extended to the whole right lobe and 131I scintigraphy has detected a "hot" nodule and a partial suppression of131I uptake in the left lobe. Serum TSH levels (RIA) were undetectable (<1.0µUI/mL), but total T3 (190ng/dL) and T4 (8.5µg/dL) were normal. The patient underwent a partial thyroidectomy and an adenomatous nodule was found with a small central nucleus (7mm) hosting a papillary carcinoma. Whole body scans detected only residual thyroid uptake and the patient was subsequently treated with 100mCi of 131I. The patient has been on replacement therapy with 150µg of L-thyroxine and free of tumor recurrence for 12 years after surgery.

In conclusion:

the present report confirms other published cases in which the presence of a hot thyroid nodule does not exclude the concomitance of a well-differentiated thyroid carcinoma.