SPORADIC MEDULLARY THYROID CARCINOMA IN GRAVES' DISEASE.

Introduction: Graves' disease (GD) and concomitant thyroid nodules can be found in up to 44% of all cases, of which up to 17% are determined as malignant tumors. Medullary thyroid carcinoma (MTC) seems to be found extremely rarely, which causes belated diagnosis. Case presentation: A 50-year-old man was diagnosed with GD. Neck ultrasound revealed suspicious thyroid nodule, a fine needle aspiration biopsy was performed, and it revealed microfollicular hyperplasia, Bethesda IV. The patient was operated on and the histological examination confirmed MTC. Genetic testing revealed the sporadic form of MTC. Six weeks after the initial surgery, elevated tumor markers confirmed the persistence of the disease. The patient underwent a pyramidal lobe removal with a unilateral central compartment lymph node dissection. Histological analysis confirmed typical changes of MTC and a spread of the disease. 2 months after the lymphadenectomy, tumor markers and imaging examination revealed suspicious lymph nodes; this discovery was followed by a bilateral lymph nodes dissection and persistence of MTC confirmation. Conclusion: An early detection of sporadic MTC with concomitant GD is challenging. We want to emphasize the benefits of calcitonin (Ctn) measurement in the blood sample and a Ctn immunocytochemistry detection in the case of an autoimmune thyroid disease and suspicious thyroid nodule before the radical treatment, despite the lack of universal recommendations for routine Ctn measurement, in order to reach an earlier diagnosis of the cancer, and to perform a more radical surgical treatment.