Sporadic Medullary Thyroid Carcinoma in Grave’s Disease -Report of a case-

A 60-year-old man who noted numbness and dyskinesia of his left-hand fingers was admitted to a hospital. After anticoagulant therapy and medication with L-3, 4-dihydroxyphenylalanine (L-DOPA) were started, his symptoms didn’t improve. He was introduced to our institution with gait disturbance and difficulty of articulating properly. L-DOPA was administered under a diagnosis of multiple system atrophy by magnetic resonance imaging. He was also diagnosed as Graves’ disease with hyperthyroidism and expression of TSH receptor antibodies. Cervical ultrasonography revealed diffuse thyroid enlargement with abundant blood flow, which was consistent with Graves’ disease. A nodule of 6.3 x 8.3 x 9.2mm was also detected in the middle of the right lobe. The nodule was diagnosed as medullary thyroid carcinoma (MTC) by fine needle aspiration cytology (FNAC). The serum calcitonin and CEA level were elevated. We diagnosed sporadic MTC because lacking of pituitary or adrenal tumor, and family history of MTC. After medication for Graves’ disease, total thyroidectomy with central lymph nodes dissection was performed. Histopathological examination diagnosed as a MTC the diameter of tumor was 9 mm in the middle of the right lobe without extra thyroidal extension. Most of the thyroid cancers with Graves’ disease have been reported to be papillary thyroid cancer. The case of MTC with Graves’ disease is very rare with only 12 cases having been reported. We report the case of sporadic MTC with Graves’ disease which accidentally diagnosed by episode of multiple system atrophy.