Brown Tumors or Bone Metastases in Context of Parathyroid Carcinoma: A Diagnostic Challenge

Parathyroid carcinoma is a rare cause of primary hyperparathyroidism. When this malignancy is diagnosed, often there are distant metastases (usually liver and/or bone). Brown tumor is a localized form of osteitis fibrosa cystica; classic manifestation in bone of excess parathyroid hormone and this is a bening pathology. We encountered an unusual case of parathyroid carcinoma with images that mimicked metastatic bone tumors, whose differential diagnosis with brown tumor may be complicated. Positron emission tomography/computed tomography (PET/CT) scan was requested for the evaluation of fluorodeoxyglucosa uptake of these lesions. PET/CT images showed multiple hypermetabolic images that mimicked multiple skeletal metastasis but brown tumors could not be dismissed.