Concomitant hyperparathyroidism due to occult parathyroid adenoma detected by technetium-99m sestamibi single-photon computed tomography/computerized tomography in a patient with papillary thyroid carcinoma

Although the occurrence of thyroid and parathyroid diseases is common, concomitant parathyroid adenoma and papillary thyroid carcinoma is rare. We report the case of a 77-year-old Thai woman who was diagnosed to have papillary thyroid carcinoma and postoperative hypercalcemia. The primary hyperparathyroidism was initially overlooked but was subsequently confirmed to be due to a single occult parathyroid adenoma demonstrated on technetium-99m sestamibi (Tc-99m MIBI) parathyroid scintigraphy. Thus, preoperative evaluation of parathyroid disease should be performed if there is evidence of hypercalcemia prior to the thyroid surgery. Presurgical evaluation with Tc-99m MIBI parathyroid single-photon computed tomography/computerized tomography imaging has a definite role in localizing a hyperfunctioning parathyroid gland in the cases of primary hyperparathyroidism.