A 36-year-old woman comes to the office due to fatigue and neck discomfort. Her symptoms began several weeks ago following an upper respiratory infection. The patient's medical history is unremarkable and she takes no medications. She works as a nuclear medicine technician, has a current 20-pack-year smoking history, and does not use alcohol or illicit drugs. There is no family history of thyroid cancer, but the patient's mother has hypothyroidism treated with thyroid replacement therapy.
Vital signs are normal. On examination, the thyroid gland is low lying and difficult to palpate. There is no cervical lymphadenopathy and the remainder of the examination is unremarkable.
Laboratory results show a TSH of 12 µU/mL and free T4 of 1.1 ng/dL (normal: 0.9-2.4). Ultrasound reveals 2 nodules in the right thyroid lobe, each measuring 1.7 cm in maximal diameter, and a 1.4 cm nodule in the left lobe. All of the nodules are hypoechoic without internal vascularity or microcalcification.
Which of the following increases the risk for thyroid cancer in this patient?

Question

A 36-year-old woman comes to the office due to fatigue and neck discomfort.  Her symptoms began several weeks ago following an upper respiratory infection.  The patient's medical history is unremarkable and she takes no medications.  She works as a nuclear medicine technician, has a current 20-pack-year smoking history, and does not use alcohol or illicit drugs.  There is no family history of thyroid cancer, but the patient's mother has hypothyroidism treated with thyroid replacement therapy.
Vital signs are normal.  On examination, the thyroid gland is low lying and difficult to palpate.  There is no cervical lymphadenopathy and the remainder of the examination is unremarkable.
Laboratory results show a TSH of 12 µU/mL and free T4 of 1.1 ng/dL (normal: 0.9-2.4).  Ultrasound reveals 2 nodules in the right thyroid lobe, each measuring 1.7 cm in maximal diameter, and a 1.4 cm nodule in the left lobe.  All of the nodules are hypoechoic without internal vascularity or microcalcification.
Which of the following increases the risk for thyroid cancer in this patient?

Quizplus · Accepted Answer

11ec193a_97a3_1e4b_853d_47a869ae2057_MD0002_00 In the evaluation of thyroid nodules, a number of patient characteristics have been associated with an increased risk of malignancy. Prominent among them is history of ionizing radiation exposure to the head and neck in childhood (eg, cancer treatment, nuclear fallout). Family history of thyroid cancer and cancer syndromes also increase the risk (eg, multiple endocrine neoplasia type 2 is associated with medullary thyroid cancer). In addition, an elevated TSH (as in this patient) is associated with a higher likelihood of malignancy, whereas a suppressed TSH suggests a possible hyperfunctioning nodule, which is typically benign. Other factors associated with malignancy are noted in the table. This patient also has ultrasound findings associated with increased risk of malignancy, including size >1 cm and hypoechoic echotexture. This patient should therefore be considered for fine-needle aspiration of the nodules. (Choice B) Radiology technicians who frequently hold patients during roentgenogram procedures may have a moderately increased risk of thyroid cancer. In contrast, exposure to radioiodine isotopes used in nuclear diagnostics is not associated with increased risk. (Choice C) The risk of thyroid cancer is similar in patients with a solitary thyroid nodule compared to those with a multinodular goiter. (Choice D) Upper respiratory infections commonly precipitate subacute (de Quervain) thyroiditis, which may present as a painful goiter. Although concurrent subacute thyroiditis may have brought this patient's nodules to attention, it would not increase the risk of malignancy. (Choice E) Although benign nodules are more common in smokers, smoking and alcohol intake have not been shown consistently to increase the risk for thyroid cancer (and may be associated with lower risk). Educational objective: Major risk factors for thyroid cancer in patients with thyroid nodules include a history of radiation exposure or a family history of thyroid cancer. A higher serum TSH level is associated with increased risk of malignancy in a thyroid nodule. __________ References: Risk factors for thyroid cancer: an epidemiological review focused on nutritional factors. (http://www.ncbi.nlm.nih.gov/pubmed/18766448)

A 36-Year-Old Woman Comes to the Office Due to Fatigue