Subacute thyroiditis was identified through histological examination of the right thyroid lobe, removed in connection with treatment of a young woman for thyroid carcinoma. She had received an mRNA vaccination against SARS-CoV-2 six days previously.
A previously mainly healthy woman in her thirties was referred for an ultrasound scan after discovering a lump on her throat. An ultrasound scan revealed changes characteristic of thyroiditis and a hypoechoic nodule measuring 7 x 13 mm in the left lobe. The left thyroid lobe was extirpated after a cytological examination of fine-needle aspirate from the nodule revealed papillary thyroid carcinoma (not shown).
The procedure and post-operative course were without complications. On analysis, thyroid function markers showed an elevated value for antibodies against thyroid peroxidase (anti-TPO) of 623 kIU/L (reference range < 35), a finding associated with Hashimoto's thyroiditis. Thyroid-stimulating hormone (P-TSH) varied within the range 3.2–4.7 mIU/L (0.35–3.6), and P-fT4 (tetraiodothyronine) varied within the range 9.5–13 pmol/L (9–19). This was consistent with latent hypothyroidism. A histological examination confirmed a papillary carcinoma (not shown) and Hashimoto's thyroiditis (Figure 1).
The patient was put on levothyroxine therapy. After an interdisciplinary assessment, a complementary hemithyroidectomy was recommended prior to radioactive iodine therapy. Three months after the first procedure, and six days before unilateral complementary lobectomy of the right lobe, the patient received her first dose of the Pfizer/BioNTech vaccine against the SARS-CoV-2 virus. Preoperatively, P-TSH was 20 mIU/L (0.35–3.6 × 10−3), PfT4 10 pmol/L (9–19), and sedimentation rate 6 mm/h (1–17).
The description of the procedure indicated peroperative findings consistent with thyroiditis and fibrosis. The surgery took place without complications. A histological examination revealed changes consistent with subacute thyroiditis (Figure 2), but no evidence of a malignant tumour.
The patient was not aware of having had any COVID-19 infection, and there were no symptoms or biochemical findings to indicate a recently experienced or ongoing infection with other aetiology.
The patient has consented to the publication of the article. The article has been peer-reviewed.