Giant mediastinal parathyroid adenoma in a woman with hypercalcemia.

A 43-year-old woman was hospitalized because of muscle weakness that gradually worsened in the preceding 4 months. The diagnostic work-up revealed hypercalcemia, an elevated serum intact parathormone level, and a mediastinal mass on chest CT images. Further investigation with Tc-99m pertechnetate and Tc-99m tetrofosmin subtraction scintigraphy showed radionuclide accumulation in a large area of the mediastinum. The patient underwent surgery to remove a giant parathyroid adenoma (6 x4.5 x 2.8 cm). The patient has been followed for 2 years, with serum calcium and intact parathormone values in the normal range.