Brown tumors mimicking bone metastases.

Brown tumors are rare skeletal manifestations of hyperparathyroidism (HPT) that may mimic cancer metastasis. Here, we present a 52-year-old woman with HPT and multiple foci of technetium uptake due to brown tumors on bone scintigraphy. Screening tests were negative for cancer and serum parathormon (PTH) measurement; parathyroid ultrasonography and scintigraphy suggested HPT. A chief cell adenoma in right and hyperplasia in the left parathyroid glands were surgically removed after which hungry bone syndrome emerged. Biopsy of the femur lesion during an open reduction with fixation operation due to a fracture established the diagnosis of a brown tumor. Brown tumors are important to consider in the evaluation of patients presenting with multiple foci of uptake on bone scanning and without an established primary neoplasm.