Brown tumors in primary hyperparathyroidism initially interpreted as bone metastases and multiple gigantocelular tumors: case report.

Brown tumors or osteitis fibrosa cystica are a rare bone metabolism disorder that may mimic cancer metastasis. It represents a late manifestation of prolonged and mostly unrecognized hyperparathyroidism. In this case report we present a 44-year-old female patient with multiple lesions detected on bone scintigraphy and ¹⁸F- FDG-PET/CT, initially interpreted as a bone metastatic disease, rather than multiple gigantocellular bone tumors. Additionally, the presented case emphasizes the importance of a multidisciplinary approach in diagnosing brown tumors as part of hyperparathyroidism, and the treatment decision.