SAT-362 - Brain Metastases in Radioiodine Refractory Papillary Thyroid Carcinoma : A Multimodal Approach

Background: Brain metastases from papillary thyroid carcinoma (PTC) are rare and usually reflect biologically aggressive, radioiodine (RAI)–refractory disease with limited prospective data to guide optimal management. Treatment decisions are often individualized through multidisciplinary discussion.

Case: A 53-year-old man with aggressive PTC underwent multiple thyroid cancer resections between 2021 and 2022, followed by RAI therapy and locoregional external beam radiation therapy (EBRT) in 2022 for persistent disease.Serial surveillance PET imaging, most recently in January 2025 demonstrated no suspicious FDG uptake in the surgical bed or cervical lymph nodes and no FDG-avid distant metastases. In early May 2025, he presented with syncope associated with progressively worsening headache, nausea, and vomiting. Cross-sectional neuroimaging revealed right frontal and left occipital intracranial metastases with surrounding vasogenic edema and mass effect, prompting urgent multidisciplinary evaluation involving endocrinology, neurosurgery, radiation oncology, and medical oncology. The patient underwent left occipital craniotomy and right frontal mini-craniotomy with gross total resection of both lesions. Histopathologic examination confirmed metastatic papillary thyroid carcinoma consistent with the primary tumor.
Adjuvant cranial EBRT was delivered to both resection cavities (30 Gy in 5 fractions) in July 2025. Treatment was completed as planned without interruptions, acute neurological deterioration, or significant radiation-related toxicity.

Outcome: Follow-up computed tomography and serial magnetic resonance imaging demonstrated reassuring postoperative evolution, including interval contraction of the surgical cavities, absence of residual or enhancing disease, resolution of vasogenic edema, and no evidence of new or progressive intracranial metastases. Clinically, the patient experienced sustained resolution of headaches and remained neurologically stable on repeated examinations, without focal deficits or seizures. Following multidisciplinary tumor board review, a strategy of close radiographic surveillance with planned interval MRI was recommended, given ongoing intracranial stability.

Conclusion: This case highlights the potential for durable radiographic disease control in selected patients with RAI-refractory PTC and brain metastases managed through a multidisciplinary approach. Timely neurosurgical resection combined with adjuvant cranial EBRT and structured surveillance may offer meaningful disease control in this rare and clinically challenging presentation.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*