Ultrasound Findings of a Brown Tumor in the Metatarsal Bone due to Primary Hyperparathyroidism: A Case Report.

Brown tumor is a benign, nonneoplastic lesion resulting from hyperparathyroidism, typically found in long bones, clavicles, ribs, pelvis, and the mandible. We present a case of brown tumor secondary to primary hyperparathyroidism, with the initial presentation in the right metatarsal bone. We then describe and summarize the characteristic ultrasound features of brown tumors observed in this case. Ultrasound can detect characteristic bone destruction and typical cystic formations in the diagnosis of brown tumors, providing valuable information for the diagnosis of this condition.