Abstract
The introduction of tumor necrosis factor-alpha (TNF-α) targeting drugs has given new opportunities in the treatment of various inflammatory rheumatic diseases and has been the most important development in the treatment of ankylosing spondylitis (AS). However, the increasing use and longer follow-up periods of treatment also pose risks of developing various adverse effects, ranging from common ones, including infections, to uncommon thyroid neoplasms. Adalimumab (ADA), a fully human monoclonal antibody targeted against TNF-α, is indicated for AS. We describe the case of a patient with AS who developed a papillary thyroid carcinoma (PTC) while on therapy with ADA. Cervical lymphadenopathy and a heterogeneous nodule in the right thyroid lobe were detected in the 48-year-old female patient who had been using ADA (40 mg subcutaneously every 2 weeks) for 2 years with the diagnosis of AS. Fine-needle aspiration cytology confirmed PTC. ADA treatment was discontinued, and a total thyroidectomy surgery was performed. We believe that the thyroid gland should also be taken into consideration while screening for malignancy before and during TNF inhibitors (TNFi).