Brown Tumor Induced by Hyperparathyroidism Detected by 68Ga-FAPI-04 PET/CT

A 50-year-old woman presented with persistent left hip pain. MRI suggested metastatic lesions or hematologic disease. Further evaluation with 68Ga-FAPI-04 PET/CT revealed multiple skeletal lesions with radiotracer uptake and a non-avid low-density mass in the right parathyroid area. Elevated parathyroid hormone, hypercalcemia, and a 99mTc-sestamibi-avid right parathyroid mass led to a diagnosis of right parathyroid adenoma causing secondary brown tumors. Surgical removal of the parathyroid mass confirmed the diagnosis, highlighting the efficacy of 68Ga-FAPI-04 PET imaging in detecting brown tumors.