Brown tumors in nuclear medicine: a systematic review.

Brown tumors (BT) are abnormal bone-repair processes and a consequence of hyperparathyroidism. The diagnosis of these lytic lesions in nuclear medicine, while a challenge, is not so rare, because functional imaging is used both in the management of cancer and hyperparathyroidism. The main objective of this review is to summarize the knowledge and the evidence concerning BT and the different imaging modalities in nuclear medicine. A systematic review was performed in Embase, PubMed and Google Scholar from 2005 to 2022. We included articles describing BT in the following imaging modalities: [18 F]-fluorodeoxyglucose PET/CT, [18 F]-fluorocholine or [11 C]-fluorocholine PET/CT, [99m Tc]-Sestamibi scintigraphy, bone scan, [18 F]-sodium fluoride PET/CT, [68 Ga]-FAPI PET/CT; [68 Ga]-DOTATATE PET/CT; [11 C]-methionine PET/CT. For each modality, appearance, avidity for radiotracer, available quantitative parameters and imaging evolution after parathyroidectomy were collected and analyzed. Fifty-two articles were included for a total of 392 BT lesions. If the diagnosis of BT is evoked on a known lesion, performing a [18 F]-fluorocholine PET/CT imaging seems the most appropriate. In [18 F]-fluorodeoxyglucose, [18 F]-fluorocholine, [18 F]-sodium fluoride PET/CT and bone scan, BT can mimic metastatic disease. BT uptakes appear reversible after parathyroidectomy, with a more or less rapid decrease depending on the imaging modality used.