Endocrine Abstracts

Introduction: Amyloid goiter is a rare entity caused by massive amyloid infiltration of the thyroid gland. In some cases, differential diagnosis can be challenging. In this report, we present a patient with amyloid goiter caused by secondary amyloidosis.

Case: A 48-year-old male patient was admitted to our hospital with the complaints of neck swelling, pain, and mild dysphagia that started three weeks after the SARS-Cov-2 infection and continued for one month. The patient had a history of Crohn’s disease, ankylosing spondylitis and renal amyloidosis. He was on hemodialysis for 8 years. On physical examination, the thyroid gland was bilaterally palpable and tender. Laboratory tests were as follows: C-reactive protein 55 mg/l, sedimentation 50 mm/hr, TSH 0.02 mU/l, free T4 0.76 ng/dl, free T3 2.17 ng/l. Anti-thyroid peroxidase (TPO) and TSH receptor antibody were negative. Ultrasound showed an enlarged thyroid gland with hyperechogenicity of the parenchyma and normal vascularity. Thyroid scintigraphy revealed low uptake. Subacute thyroiditis was considered in the patient. As the administration of ibuprofen did not ameliorate his symptoms, oral metilprednisolone (32 mg/day) was initiated. Afterwards, low-dose levothyroxine replacement was started for hypothyroidism. Despite using steroid (methylprednisolone at a maximum dose of 64 mg/day) for more than one month, his symptoms did not significantly relieve and the patient was hospitalized. Computed tomography scan of the neck showed diffuse enlargement of the thyroid gland and parenchymal heterogeneity. Fine-needle aspiration of the thyroid gland was performed, but the findings were non-specific. After that, tru-cut biopsy was planned for the patient. Pathological analysis revealed amyloid goiter. Positive staining with Congo red was obtained. Immunohistochemical staining patterns were consistent with amyloid AA. The patient, who was evaluated together with the general surgery department, was discharged with a total thyroidectomy planned for symptomatic amyloid goiter. After a short time, it was learned that the patient died due to myocardial infarction in another center.

Conclusion: In some cases, it can be difficult to distinguish amyloid goiter from subacute thyroiditis and other diseases. Amyloid goiter should be kept in mind in patients present with rapid thyromegaly and have a history of chronic inflammatory disease that may be associated with secondary amyloidosis. Fine-needle aspiration has a limited role in diagnosis. Either a core-needle biopsy or surgical specimen is often necessary.