Brain metastasis as the initial presentation of papillary thyroid carcinoma, tall cell variant: Case report and brief literature review

Brain metastasis as the initial manifestation of papillary thyroid carcinoma (PTC) is exceedingly rare. We report a 49-year-old female who presented with progressive headaches, confusion, and right-sided weakness. A brain MRI showed a single ring-enhancing lesion in the left parietal region, accompanied by a noticeable mass effect. This finding raised concern for either primary brain cancer or a metastatic tumor from an unknown source. Craniotomy with gross total resection was performed, and pathology revealed metastatic PTC, tall-cell variant (TCV), which was later confirmed by thyroglobulin and TTF-1 immunohistochemistry (IHC). On further evaluation, a primary thyroid tumor was found, and staging revealed pulmonary involvement. The patient underwent total thyroidectomy with central neck dissection, which was followed by radioactive iodine therapy, adjuvant brain radiotherapy, and TSH suppression. Despite all treatments, her condition progressed, and she died 18 months after diagnosis. This case highlights the importance of considering PTC in the differential diagnosis of brain lesions, even in the absence of thyroid-related symptoms, while focusing on the aggressive treatment clinical course of PTC. This article further discusses the background and pathogenesis of this condition while comparing the case with the current literature.