A rare case of hyperfunctioning papillary carcinoma of the thyroid gland

We report a rare case of hyperfunctioning papillary carcinoma of the thyroid. A 32-year-old man was referred to our hospital for the treatment of a painless mass in the left neck, which had been detected on routine physical check-up. Cervical ultrasonography and computed tomography showed a solid tumor with calcification in the left lobe of the thyroid gland. Serum examinations demonstrated hyperthyroidism with a high level of thyroglobulin. Fine needle aspiration biopsy revealed a cytological diagnosis of class II. Tc-99m scintigraphy showed a hot nodule in the left lobe, which implied that the tumor was a hyperfunctioning thyroid tumor. Left lobectomy of the thyroid gland was performed to treat the hyperfunctioning tumor. Postoperative pathological examinations revealed a follicular variant papillary carcinoma. Postoperative thyroid function became within the normal range. Although hyperfunctioning thyroid carcinomas are rare, it is important to correctly diagnose them and to perform appropriate surgica...