Thyroid Nodule in a 48-Year-Old Woman (Case 14)

Chapter 25 Thyroid Nodule in a 48-Year-Old Woman (Case 14)



Mira Milas, MD, Deebeanne M. Tavani, DO, PhD, Paula M. Termuhlen, MD




Differential Diagnosis









Colloid nodule/cyst Thyroid cancer Goiter



Speaking Intelligently


When I’m referred a 48-year-old woman who presents with a thyroid nodule, I obtain an ultrasound and a thyroid-stimulating hormone (TSH), which is a biochemical marker that tells me about the patient’s thyroid function.


When the TSH is normal, I obtain a fine-needle aspiration biopsy (FNA) for any thyroid nodule that is 1.0 cm or greater in diameter. For the patient with an elevated TSH (indicative of hypothyroidism), I obtain an FNA and I treat the hypothyroidism.


If the TSH is abnormally low, which suggests a possible hyperthyroid state, I do not go directly to FNA of a nodule, because the nodule in question may be “hot” (an autonomously functioning nodule), in which case it is unlikely to be carcinoma. Instead, I obtain an 123I uptake and scan and I attempt to correlate the nodule in question with the scan. If the nodule in question is “hot,” I do not perform an FNA. I simply treat the hyperthyroidism with radioactive iodine. If, on the other hand, the hot nodule on scan and the nodule (determined by physical examination or ultrasonography) do not correlate, I obtain an ultrasound-guided FNA on any “cold” nodule >1.0 cm.



PATIENT CARE



Clinical Thinking



• The prevalence of thyroid abnormalities, especially among women, can be as high as 40%. The majority of nodules are nonpalpable and benign. Only 10% of thyroid nodules are cancerous. Incidence of malignancy increases with age.

• Findings on ultrasonography that are suspicious for malignancy include microcalcifications <2 mm, hypoechoic nodules with irregular margins, and increased intranodal vascularity.

• The only definitive dx of thyroid cancer preoperatively is by FNA.

• Thyroid FNA classifications: benign, indeterminate, malignant, nondiagnostic.

• The presence of a multinodular thyroid gland does not exclude malignancy.

• The goals of evaluating a thyroid nodule in a 48-year-old woman are to exclude the presence of thyroid cancer and to determine whether the underlying dx will require surgery. Not all thyroid nodules need to be removed.


History



• Consider the broader details of endocrine hx. Does the patient have a hx of hypo- or hyperthyroidism or previous thyroid nodules? Is there a personal or family hx of other endocrine disorders?

• Is there a hx of face or neck irradiation as a child or tx with radiation as an adult?

• Are there symptoms of obstruction (dysphagia, difficulty breathing), changes in voice, rapid growth of the lesion?

• If a patient has had a prior known hx of thyroid cancer and is now presenting with a new thyroid nodule, the details of the previous dx and tx are essential.


Physical Examination



• Examine the patient while she is sitting and facing you. The landmarks are the laryngeal cartilage and the cricoid cartilage. Just below the cricoid cartilage is the thyroid isthmus. The thyroid lobes are adjacent to the trachea.

• Ask the patient to swallow. The only structures that move in the neck during swallowing are the larynx and the thyroid gland. Observe possible movement of the nodule during swallowing.

• Palpate the neck standing in back of the patient. Gently palpate the right and left lobes of the thyroid and the isthmus, noting any enlargement, masses, or asymmetry.

• Gently bend the head to each side, attempting to palpate behind the sternocleidomastoid muscle. Palpate the supra- and subclavicular areas, the submandibular areas, and the submental area for any enlarged lymph nodes or masses.

• Have the patient demonstrate the area of concern and reexamine the patient in the position that the area of concern is best appreciated.

• Be sure to tell the patient what you find, even if the results of her examination are normal.


Tests for Consideration


Thyroid function testing:














• Free T4: The free or active thyroid hormone; not affected by variations in thyroid hormone binding proteins. Free T4 is the test to follow when you are treating hypo-or hyperthyroidism.
 $150

• TSH: TSH is an anterior pituitary glycoprotein that is regulated by hypothalamic hormones and principally by feedback of circulating thyroid hormones. Low TSH implies hyperthyroidism as TSH is being turned off by excess circulating T4. High TSH implies insufficient T4 (hypothyroid state).
 $130

• Thyroglobulin (Tg) is a glycoprotein that is secreted uniquely by thyroid follicular cells. The main clinical usefulness of Tg measurements is for following the status of patients with differentiated thyroid cancer who have had a thyroidectomy and remnant ablation.
 $145



IMAGING CONSIDERATIONS








→ Neck ultrasonography: Ultrasonography of the thyroid should use high-frequency imaging to show great detail and the size of the gland, cystic and solid nature of masses, as well as calcifications that shadow on ultrasonography. Also used for image-guided biopsy/aspiration for nonpalpable lesions.

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Mar 20, 2017 | Posted by in GENERAL SURGERY | Comments Off on Thyroid Nodule in a 48-Year-Old Woman (Case 14)

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