Differentiated thyroid carcinoma with functional autonomy.

Objective: To present a case of papillary carcinoma in an autonomously hyperfunctioning thyroid nodule.

Methods: We chronicle the clinical and laboratory findings in a patient with a painless neck mass, with a particular focus on the pathologic findings after surgical removal of the right thyroid lobe.

Results: A 39-year-old woman had an enlarging nodule of the right thyroid lobe. Results of thyroid function tests suggested subclinical hyperthyroidism. Two months later, the patient complained of increasing swelling in the neck (but still had no symptoms suggestive of hyperthyroidism). Thus, resection of the right thyroid lobe was performed. Pathologic analysis disclosed low-grade papillary thyroid carcinoma within the nodule, with a small rim of compressed inactive-appearing thyroid tissue surrounding the nodule. Subsequently, she underwent total thyroidectomy and follow-up care for thyroid carcinoma.

Conclusion: Although solitary hyperfunctioning nodules of the thyroid gland are usually considered benign, the current case suggests that the diagnosis of autonomous thyroid nodules does not preclude thyroid carcinoma in a functioning nodule.