Subacute Thyroiditis Presenting as a Painful Hot Nodule
Subacute thyroiditis is the most common cause of non-autoimmune thyroiditis. In addition to the typical clinical signs, characteristic ultrasound findings of subacute thyroiditis include the presence of an ill-defined hypoechoic area with a nonhomogeneous pattern. Recently, Ruchala et al. demonstrated the usefulness of sonoelastography for the diagnosis of subacute thyroiditis. The cytological features found during thyroid fine-needle aspiration include the presence of large multinucleated giant cells or epithelioid granulomas, but the absence of these findings does not exclude the diagnosis of subacute thyroiditis. Generally speaking, elevated serum thyroid hormones, a tender enlarged thyroid, and low radioiodine thyroid uptake are characteristic of subacute thyroiditis. Although cases with these typical signs may present little difficulty for a diagnosis of subacute thyroiditis, this disorder does not always present in a classic fashion and may lead to difficulties during diagnosis. Sometimes the diagnosis may be less clear, particularly when the primary presenting symptom is a solitary thyroid nodule in conjunction with normal thyroid function, thyroglobulin levels, and a normal ESR.
Previously, thyroid nodules have been identified in association with subacute thyroiditis and, in some patients with subacute thyroiditis, only one nodule is present. For example, Liel reported a case that presented with the coexistence of subacute thyroiditis and an autonomously functioning thyroid nodule. More often, localized forms of subacute thyroiditis present as painful and tender "cold" thyroid nodules, which disappear following recovery. However, subacute thyroiditis that presents as a painful "hot" nodule is exceedingly rare and has not been reported. In this case, laboratory tests, including white blood cell count, neutrophil percentage, thyroid function, thyroglobin levels, and ESR, were normal and non-diagnostic but the clinical findings (neck pain, thyroid tenderness, and fatigue) led to the consideration of a diagnosis of subacute thyroiditis. Therefore, further work-ups were completed including an ultrasound examination of the neck, thyroid scintigraphy with 99 m-Tc, and fine needle aspiration cytology of the nodule. Ultrasound examination demonstrated a dyshomogeneous and hypoechoic mass in the thyroid, which was characteristic of subacute thyroiditis, and thyroid scintigraphy showed a focal accumulation of radiotracer uptake in the thyroid nodule. The histological features of the nodule were also typical of subacute thyroiditis. Therefore, a diagnosis of localized subacute thyroiditis was given and the patient was prescribed prednisone, which resulted in the disappearance of the hot thyroid nodule. The treatment of subacute thyroiditis is essentially symptomatic and includes non-steroidal anti-inflammatory agents or, occasionally, glucocorticoids if the symptoms are prolonged or severe. In the current case, treatment with steroids resulted in an amelioration of the patient's symptoms and the disappearance of the thyroid nodule after 2 months.
Based on the course and the clinical presentation of the present case, a diagnosis of subacute thyroiditis could be established. The disappearance of the thyroid nodule following prednisone treatment further confirms the diagnosis of subacute thyroiditis following presentation with a thyroid hot nodule. Here, the appearance of the hot thyroid nodule was unusual in that it did not show the usual pattern of low uptake during radioisotope scanning. This case demonstrates that subacute thyroiditis may present as a solitary painful hot nodule in conjunction with normal thyroid function, thyroglobulin levels, and ESR and should, therefore, be considered in the differential diagnosis of such lesions.
The mechanism of 99 mm-Tc localization in subacute thyroiditis is not known. Tonami et al. reported two cases of subacute thyroiditis in which thyroid scintigrams with 201TI chloride showed increased radionuclide activity in the affected areas but decreased activity in the affected areas following thyroid scintigrams with 99 m-Tc. It was presumed that this is primarily due to increased membrane permeability in the inflammatory lesion without the apparent destruction of the thyroid gland, which is typically indicated by normal thyroglobulin levels and thyroid function in the patient. Therefore, the present case suggests the clinical and pathological heterogeneity of subacute thyroiditis.
In conclusion, this case demonstrates that subacute thyroiditis should be considered as a differential diagnosis following presentation with a solitary painful thyroid hot nodule in conjunction with normal thyroid function, thyroglobulin levels, and ESR. Additionally, this case emphasizes the heterogeneous pattern of thyroid imaging in subacute thyroiditis.
Written informed consent was obtained by the patient for the publication of this case report and any accompanying images.
Conclusions
Subacute thyroiditis is the most common cause of non-autoimmune thyroiditis. In addition to the typical clinical signs, characteristic ultrasound findings of subacute thyroiditis include the presence of an ill-defined hypoechoic area with a nonhomogeneous pattern. Recently, Ruchala et al. demonstrated the usefulness of sonoelastography for the diagnosis of subacute thyroiditis. The cytological features found during thyroid fine-needle aspiration include the presence of large multinucleated giant cells or epithelioid granulomas, but the absence of these findings does not exclude the diagnosis of subacute thyroiditis. Generally speaking, elevated serum thyroid hormones, a tender enlarged thyroid, and low radioiodine thyroid uptake are characteristic of subacute thyroiditis. Although cases with these typical signs may present little difficulty for a diagnosis of subacute thyroiditis, this disorder does not always present in a classic fashion and may lead to difficulties during diagnosis. Sometimes the diagnosis may be less clear, particularly when the primary presenting symptom is a solitary thyroid nodule in conjunction with normal thyroid function, thyroglobulin levels, and a normal ESR.
Previously, thyroid nodules have been identified in association with subacute thyroiditis and, in some patients with subacute thyroiditis, only one nodule is present. For example, Liel reported a case that presented with the coexistence of subacute thyroiditis and an autonomously functioning thyroid nodule. More often, localized forms of subacute thyroiditis present as painful and tender "cold" thyroid nodules, which disappear following recovery. However, subacute thyroiditis that presents as a painful "hot" nodule is exceedingly rare and has not been reported. In this case, laboratory tests, including white blood cell count, neutrophil percentage, thyroid function, thyroglobin levels, and ESR, were normal and non-diagnostic but the clinical findings (neck pain, thyroid tenderness, and fatigue) led to the consideration of a diagnosis of subacute thyroiditis. Therefore, further work-ups were completed including an ultrasound examination of the neck, thyroid scintigraphy with 99 m-Tc, and fine needle aspiration cytology of the nodule. Ultrasound examination demonstrated a dyshomogeneous and hypoechoic mass in the thyroid, which was characteristic of subacute thyroiditis, and thyroid scintigraphy showed a focal accumulation of radiotracer uptake in the thyroid nodule. The histological features of the nodule were also typical of subacute thyroiditis. Therefore, a diagnosis of localized subacute thyroiditis was given and the patient was prescribed prednisone, which resulted in the disappearance of the hot thyroid nodule. The treatment of subacute thyroiditis is essentially symptomatic and includes non-steroidal anti-inflammatory agents or, occasionally, glucocorticoids if the symptoms are prolonged or severe. In the current case, treatment with steroids resulted in an amelioration of the patient's symptoms and the disappearance of the thyroid nodule after 2 months.
Based on the course and the clinical presentation of the present case, a diagnosis of subacute thyroiditis could be established. The disappearance of the thyroid nodule following prednisone treatment further confirms the diagnosis of subacute thyroiditis following presentation with a thyroid hot nodule. Here, the appearance of the hot thyroid nodule was unusual in that it did not show the usual pattern of low uptake during radioisotope scanning. This case demonstrates that subacute thyroiditis may present as a solitary painful hot nodule in conjunction with normal thyroid function, thyroglobulin levels, and ESR and should, therefore, be considered in the differential diagnosis of such lesions.
The mechanism of 99 mm-Tc localization in subacute thyroiditis is not known. Tonami et al. reported two cases of subacute thyroiditis in which thyroid scintigrams with 201TI chloride showed increased radionuclide activity in the affected areas but decreased activity in the affected areas following thyroid scintigrams with 99 m-Tc. It was presumed that this is primarily due to increased membrane permeability in the inflammatory lesion without the apparent destruction of the thyroid gland, which is typically indicated by normal thyroglobulin levels and thyroid function in the patient. Therefore, the present case suggests the clinical and pathological heterogeneity of subacute thyroiditis.
In conclusion, this case demonstrates that subacute thyroiditis should be considered as a differential diagnosis following presentation with a solitary painful thyroid hot nodule in conjunction with normal thyroid function, thyroglobulin levels, and ESR. Additionally, this case emphasizes the heterogeneous pattern of thyroid imaging in subacute thyroiditis.
Consent
Written informed consent was obtained by the patient for the publication of this case report and any accompanying images.
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