Increased 99mTc-Sestamibi Activity in Giant Cell Tumor of Bone.

A 99mTc-sestamibi parathyroid scintigraphy was performed in a 27-year-old woman to evaluate possible hyperparathyroidism. The images did not identify any parathyroid abnormality. However, an intense activity was noted in the proximal left upper extremity, which was confirmed as giant cell tumor of the proximal left humerus by pathological examination.