A Case Of Subacute Thyroiditis Suspected To Be Thyroid Tumor And Review Of Literature

Objective:To improve the understanding of atypical subacute thyroiditis and reduce missed diagnosis and misdiagnosis by analyzing the reasons for the misdiagnosis of a case of subacute thyroiditis suspected to be thyroid tumor.Methods:Summarize the clinical features,laboratory examinations,imaging findings,pathology,treatment and outcome by collecting the clinical data of 1 case of atypical subacute thyroiditis and reviewing the literature.Results:A 62-year-old woman was presented with a painless goiter that enlarged in a short period of time.On physical examination,there is a second-degree swelling of the thyroid gland,and the left lobe nodules are hard,without obvious tenderness.The examination of thyroid function showed that FT3 and FT4 increased,and TSH decreased.thyroglobulin elevated.TPOAb,TRAb,and TGAb were negative.ESR and CRP increased.Thyroid color Doppler ultrasound showed enlarged thyroid,uneven patchy hypoechoicity,and multiple abnormal lymph nodes on both sides of the neck.This suggested that it may be thyroid cancer or lymphoma.Thyroid MRI showed multiple nodules,multiple enlarged lymph nodes on both sides of the neck.And malignant thyroid tumors（lymphomas）cannot be ruled out.In order to clarify the nature of the goiter,a thyroid biopsy was performed.The pathological results showed active thyroid follicular epithelium with granuloma formation under the microscope.No clear morphological malignant evidence was found.Thyroid cancer and lymphoma can be ruled out.The patient was considered as subacute thyroiditis.The decline in thyroid ¹³¹I uptake further supported the diagnosis of subacute thyroiditis.She received symptomatic treatments such as anti-inflammatory and slowing down the heart rate.Two months later,she had no neck pain and palpitation.There was no swelling of the bilateral thyroid gland and no palpable nodules.The examination of thyroid function showed that FT3 and FT4 decreased,and TSH increased.ESR and CRP decreased.She stopped the medications.Conclusion:Subacute thyroiditis is not uncommon,and most cases can be easily diagnosed based on clinical manifestations and auxiliary examinations without pathological examinations.However,some cases are not typical and are easy to be missed and misdiagnosed.When a patient has a recent thyroid mass without inflammation such as pain and fever,and imaging shows malignant features,even if there is thyrotoxicosis and a decrease in iodine uptake rate,pathological examination is needed to confirm the diagnosis to avoid misdiagnosis and mistreatment.