Oncocytic thyroid adenoma imitating functionally active parathyroid adenoma

The authors present surgical treatment of a patient with follicular thyroid tumor and parathyroid gland adenoma. Subsequent analysis recognized oncocytic thyroid gland adenoma manifested by clinical and laboratory picture of primary hyperparathyroidism. Multinodular goiter imitating parathyroid gland adenoma when one of the nodes is located behind thyroid lobe and intrathyroid location of parathyroid gland adenoma are factors complicating differential diagnosis. Therefore, this case of thyroid gland adenoma imitating functionally active parathyroid gland adenoma illustrates the need for alertness with respect to combination and mutual imitation of tumors of thyroid and parathyroid glands requiring surgical intervention. In addition, such cases require differential diagnosis between thyroid and parathyroid neoplasms based on all available laboratory and topical methods.