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Elevated thyroid hormone levels, hypoechoic mass found in middle-aged woman
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A 49-year-old female presented to the otolaryngology clinic with a 1-month history of lower neck pressure and left-sided neck pain. She had mild upper respiratory infection symptoms without fever 3 weeks before presentation. She had no family history of thyroid disease or exposure to radiation, and she denied recent new medications or CT scans.
Stephanie L. Lee
Swetha L.
Kommareddy
Clinical presentation, test results
Thyroid ultrasound revealed an enlarged gland with a heterogeneous, hypoechoic echotexture. The right lobe measured 3.4 cm x 1.3 cm x 1.4 cm (sagittal x anterior/posterior x transverse) with a 5-mm solid nodule (Figures 1A, 1B). The left lobe was enlarged and measured 4.6 cm x 1.5 cm x 1.9 cm (sagittal x anterior/posterior x transverse) with a 2-cm hypoechoic thyroid nodule with indistinct margins and nonshadowing hyperechoic foci consistent with microcalcifications (Figures 1C, 1D). The nodule was not vascular by Doppler. The patient was referred to the endocrine clinic.
She was euthyroid clinically with an enlarged (1.5 times normal size) and firm, nontender thyroid gland with no discrete palpable nodules. Thyroid-stimulating hormone checked during this visit (6 weeks after initial symptoms) was 1.93 mIU/mL (normal reference range: 0.35 mIU/mL to 4.9 mIU/mL). The left nodule was biopsied with hypocellular cytology with atypical follicular cells.
Subacute granulomatous thyroiditis (SAT) was tentatively diagnosed based on clinical presentation and evolving ultrasound appearance. Radioactive iodine uptake was not obtained because the patient had a normal TSH. During the follow-up visit 6 weeks later, she reported improvement in her compressive symptoms and a repeat thyroid ultrasound showed decrease in size of the thyroid gland. The previously identified hypoechoic thyroid nodule and thyroid enlargement had resolved, leaving a hypoechoic gland consistent with chronic thyroiditis (Figures 1E, 1F). TSH checked at this time (3 months after initial presentation) was elevated at 4.91 mIU/mL (normal range: 0.35 mIU/mL to 4.9 mIU/mL) with a total triiodothyronine of 80 ng/dL (normal range: 83 ng/dL to 160 ng/dL) and free thyroxine of 0.81 ng/dL (normal range: 0.6 ng/dL to 1.8 ng/dL). Four weeks later she had complete resolution of her symptoms and thyroid dysfunction with a TSH of 3.13 mIU/mL. Thyroid peroxidase antibodies were minimally elevated at 10.8 IU/mL (normal: <5 IU/mL). It was concluded that the patient had complete resolution of SAT. She was advised to repeat her thyroid function tests in 6 months.
Viral illness and SAT
SAT, also known as de Quervain’s thyroiditis, is a self-limiting inflammatory condition of the thyroid gland that is often preceded by a viral illness. It is three to five times more common in women compared with men and most often occurs in middle-aged women. SAT is characterized by thyroid pain and enlargement, malaise, myalgias, fever and elevated erythrocyte sedimentation rate. It is strongly associated with HLA-B35 in many ethnic groups, and some reports show seasonal influence. SAT is self-limiting, but nonsteroidal anti-inflammatory drugs can be used for symptomatic relief from pain. Subacute granulomatous or “painful” thyroiditis can present within 4 to 8 weeks of thyrotoxicosis in early phase due to destruction of thyroid follicles and release of T4 and T3. This phase is characterized by a suppressed TSH, elevated free T4 and decreased radioactive iodine uptake. It can be followed by a brief period of euthyroidism and then mild hypothyroidism for 4 to 6 months. Thyroid function ultimately normalizes in 85% to 95% of patients within 6 to 12 months. Recurrent episodes of SAT are rare and occur in 1.6% of patients.
Thyroid ultrasound at the time of presentation of subacute thyroiditis showed an enlarged heterogeneous left lobe (A: transverse, B: sagittal) and right lobe (C: transverse, D: sagittal). A small 0.5-cm nodule (blue arrow) was located in the right lobe (A, B) and a 2-cm hypoechoic nodule (yellow arrow) was found in the left lobe (C, D). This nodule (yellow arrow) had an irregular, indistinct margin; no vascular flow (C); and nonshadowing hyperechoic foci (red arrows). Twelve weeks after presentation, her symptoms and nodules resolved leaving a normal-sized hypoechoic thyroid with normal vascular flow (1 E, F).
Reprinted with permission from: Stephanie L. Lee, MD, PhD
In SAT, the thyroid gland is usually diffusely enlarged and is characterized by pain and tenderness that can radiate to the ear and jaw. But sometimes pain and enlargement can be unilateral and the area of inflammation can migrate from one part of the thyroid gland to another. The characteristic ultrasound findings of this disease include an ill-defined hypoechoic area without vascular flow on Doppler analysis. The hypoechoic area on ultrasound usually corresponds to a tender area on the thyroid gland. Nishihara reported that the extent of hypoechoic area on an ultrasound correlates with the degree of inflammation, but it might not be reflective of thyroid dysfunction and does not predict the development of permanent hypothyroidism.
What to look for
The diagnosis of SAT is mostly based on clinical presentation and laboratory data. SAT can present sometimes as a nontender solitary thyroid nodule, as seen in our patient. In such cases, fine needle aspiration biopsy may establish the diagnosis. Cytology varies according to the stage of the disease. Fine needle aspiration biopsy results in 14 patients with SAT and thyroid nodules all contained multinucleated giant cells. Of note, multinucleated giant cells are not specific for SAT and can be seen in papillary thyroid carcinoma, Hashimoto’s thyroiditis and multinodular goiter with degenerative changes. But the multinucleated giant cells in these conditions are usually fewer in number and smaller in size. Other conditions that can cause painful, tender thyroid include infectious thyroiditis, benign or malignant thyroid nodule with hemorrhage, or rapid neoplastic growth.
SAT should be considered in any patient presenting with a tender thyroid nodule, history of viral illness, abnormal thyroid function tests and a high erythrocyte sedimentation rate. The thyroid nodule can then be followed using serial thyroid ultrasounds for 2 to 4 months. If the nodule fails to resolve on serial thyroid ultrasounds, it should be biopsied to rule out a malignancy.