Diagnostic dilemma: metastatic bone malignancy or primary hyperparathyroidism with brown tumor

Multiple osteolytic lesions are usually associated with metastatic involvement of the bone. However metabolic bone diseases should also take their place in differential diagnosis. Here, we describe a primary hyperparathyroidism case with full-blown osteolytic lesions wich was diagnosed at first sight with having metastatic bone involvement. PET CT scan and laboratory results excluded a metastatic bone malignancy. Elevated serum calcium of 13.16 mg/dl, decreased serum phoshorus of 1.4 mg/dl and high intact-PTH level of 1054.7 pg/ml pointed out primary hyperparathyroidism. Sonographic examination revealed two adenomas of 2.9 × 3.3 mmand 3.3 ×2.7 mmin the left superior and right inferior parathyroid glands, respectively. Scintigraphy confirmed the presence of adenoma on the left.