A 53-year-old man presents to the clinic with a non-tender mass in his right anterior neck. The mass has been slowly enlarging over the past 1 year. He reports no dysphagia, difficulty breathing, or changes to his voice. He also denies heat intolerance, palpitations, tremors, or diarrhea. He has hypertension and hyperlipidemia, for which he takes lisinopril and atorvastatin. He has never smoked cigarettes. His temperature is 37.1°C (98.8°F), blood pressure is 130/84 mmHg, pulse is 86/min, respirations are 12/min, and oxygen saturation is 99% on room air. Bedside ultrasound reveals a 1x2 cm hypoechogenic nodule with microcalcifications in the right thyroid lobe, which is biopsied. Pathology results are shown in Figure A. Which of the following is the most appropriate next step in management?
Repeat ultrasound in 6 months
Thyroidectomy followed by radioactive iodine
Methimazole
Radioactive iodine
Thyroidectomy followed by radioactive iodine
This patient who presents with a slowly enlarging neck mass has ultrasound (hypoechogenic nodule with microcalcifications) and histology findings (concentrically laminated calcifications called psammoma bodies) consistent with papillary thyroid carcinoma. The most appropriate next step in management would be thyroidectomy followed by radioiodine ablation.

Papillary thyroid carcinoma represents the majority of malignant thyroid cancers. They are slow-growing and are found in the hormone-producing follicular cells of the thyroid. Typically, these tumors are found incidentally on imaging. Risk factors for thyroid malignancy include a history of radiation exposure, female sex, and positive family history. Nodules with minimal uptake on radioactive iodine scan, firm and immobile solitary nodules, and rapidly growing nodules with associated hoarseness are more suggestive of thyroid malignancy. Findings on histology include empty-appearing nuclei with central clearing, psammoma bodies, and nuclear grooves. The treatment is thyroidectomy followed by radioactive iodine ablation of any remaining thyroid cells. Long-term care should include levothyroxine at a dose sufficient to suppress thyroid-stimulating hormone (TSH) release that may stimulate any remaining malignant cells.

Oakley et al. studied if relatives of patients diagnosed as having papillary thyroid carcinoma are at increased risk using a retrospective cohort study. The authors found first-degree relatives were at a 5-fold increased risk, and second-degree relatives were at a 2-fold increased risk. The authors recommend more research into optimal approaches to screening for thyroid cancers.

Figure/Illustration A is a histology section showing a psammoma body (blue circle), which are round, concentrically laminated calcifications that are formed after necrosis of papillary structures. Psammoma bodies and nuclei with central clearing (yellow circle) and nuclear grooves are common histology findings for papillary thyroid carcinoma.

Incorrect Answers:
Answer A: Levothyroxine would be the treatment of choice in hypothyroidism and is important in the long-term care of papillary thyroid carcinoma to suppress the TSH release that may stimulate any remaining malignant cells after treatment (thyroidectomy and radioactive iodine).

Answer B: Methimazole is an agent that blocks thyroid peroxidase, thus inhibiting the synthesis of thyroid hormones. It is used in the treatment of hyperthyroidism and does not have a role in the treatment of papillary thyroid carcinoma.

Answer C: Radioactive iodine is used as an adjunct after thyroidectomy in the treatment of papillary thyroid carcinoma in order to target any thyroid cells that may remain even after surgical excision. Surgery is the primary therapy for papillary thyroid carcinoma. Radioactive iodine is the primary method of therapy in cases of Grave disease, toxic adenoma, or multinodular goiter.

Answer D: Repeating an ultrasound in 6 months to assess the growth of the nodule or the development of suspicious characteristics is appropriate in cases where the ultrasound and biopsy findings are consistent with a benign thyroid nodule. The ultrasound findings of hypoechogenicity, microcalcifications, hypervascularity, and taller-than-wide nodules suggest malignancy, and together with a biopsy consistent with thyroid malignancy would warrant surgical treatment with subsequent radioactive iodine ablation.

Bullet Summary:
Papillary thyroid carcinoma is managed with thyroidectomy followed by radioactive iodine ablation and long-term levothyroxine to suppress thyroid-stimulating hormone stimulation of any remaining malignant cells.