Background. Calvarial metastases from thyroid malignancy, particularly in Hürthle cell carcinoma (HCC), are rare, with most cases affecting non-skull bones and lungs. Metastasis to the skull, especially with intracranial involvement, is exceedingly uncommon. This case highlights an unusual presentation of metastatic HCC as an extensive calvarial mass infiltrating the intracranial compartment. Case report. A 37-year-old male presented with a progressively enlarging and painful mass on his scalp over two years, growing from the size of a marble to a double-head appearance. His medical history included a neck mass present since age 12. Neurological and vital examinations were normal. CT scan and angiography showed a calcified and hemorrhagic mass supplied by the external carotid artery, destroying bilateral parietal bones and infiltrating the superior sagittal sinus and dura mater. Neck ultrasound suggested solid bilateral thyroid nodules. Histopathology of thyroid biopsy and resected tissue confirmed Hürthle cell carcinoma. A subtotal calvarial tumor resection was performed, followed by an Orticochea flap. Histopathology of the resected tissue confirmed thyroid metastasis. Post-surgery, the patient developed self-resolving right hemiparesis and acute seizures, managed with topiramate. Multidisciplinary consultation led to planned radioiodine therapy, with bevacizumab considered as an alternative if radioiodine failed. Conclusion. Calvarial metastasis is a rare manifestation of Hürthle cell carcinoma, and it can progress as a giant mass without neurological deficits. This case demonstrates the resectability of such metastasis with a favorable outcome. © 2025, Amaltea Medical Publishing House. All rights reserved.