Brain metastasis from differentiated thyroid cancer: diagnosis and treatment - one case report

Brain metastases from differentiated thyroid cancer (DTC) are rare. DTC patients with brain metastases have poor prognosis. Diagnosis and treatment of these patients should be individualized. We report diagnostic and treatment options of a 68-year-old man DTC with single brain metastasis combined with single soft tissues metastasis, multiple lungs and bones metastases. The patient underwent a comprehensive examination including post-therapeutic (after radioactive iodine, ¹³¹I (RAI) therapy) SPET/CT, ¹⁸F-FDG PET/CT and whole-body MRI with diffusion-weighted imaging (WB-MRI with DWI). At the time of reporting (October 2020) the patient has received combined treatment for metastatic disease included three RAI therapy courses (cumulative ¹³¹I activity 13 GBq), external beam radiation therapy for the bone (32 Gy) and soft tissues metastases (22.5 Gy) and proton beam therapy for brain metastasis (4 GyE, 11 fractions). Due to the disease progression RAI therapy was canceled and prescribed target therapy by tyrosine kinase inhibitor. Brain metastasis visualized as ¹³¹I, ¹⁸F-FDG and DWI positive lesion in the left temporal lobe. FDG-positive metastases showed poor response to RAI therapy regardless of the ¹³¹I uptake degree. During further disease progression we observed a partial response is maintained only in metastases on which external radiation therapy was performed including in single brain metastasis. In cases of concomitant existence of brain metastasis and extracranial multiple lesions local treatment on brain lesion is recommended as soon as possible regardless of its ¹³¹I uptake. Proton radiation therapy is one of the brain metastasis local treatment options for such patients. (author)