Study of Multimodality Imaging Features of Brown Tumor or Osteitis Fibrosa Cystica

Abstract

Introduction Brown tumor, also known as osteitis fibrosa cystica, is a rare but significant manifestation of hyperparathyroidism characterized by focal bone lesions resulting from excessive osteoclastic activity. Despite its rarity, Brown tumor poses diagnostic challenges due to its varied clinical presentations and radiographic features, often mimicking other bone lesions such as giant cell tumors or metastatic disease. Material and Methods In this study, we present a retrospective analysis of 6 cases of Brown tumor diagnosed and managed at our institution over a 12 months period from April 2022 to April 2023. Our objectives are to delineate the diverse clinical manifestations of Brown tumor, discuss diagnostic modalities utilized, treatment strategies employed, and evaluate patient outcomes. Results Five out of our six patients were females. Also 5 out of our 6 patients were under the age of 25. 2 patients presented to us with multiple lytic lesions and other 4 patients had solitary lesions. 1 patient out of 6 presented to us with pathological fracture. Only 2 out of the 6 patients had a positive sestamibi scan but Ultrasonography (USG) of the neck and MRI of the neck showed the presence of parathyroid adenoma in all the cases. Preoperative average of VAS score in this patients was 67 which was decreased to as low as 24. We performed paired t-tests on the blood investigation values and Visual Analog Scale (VAS) scores for all patients. The results were statistically significant, with values returning to normal three months post-surgery. Conclusion When radiographic evidence of a lytic lesion and hypercalcemia are present, Brown tumor should always be considered in the differential diagnosis. Brown tumor has a distinctive imaging appearance, with solid components displaying intermediate to low intensity on T1- and T2-weighted images, while the cystic components appear hyperintense on T2-weighted images and exhibit fluid-fluid levels. MRI of the neck corroborates the ultrasound findings and detects parathyroid adenomas as hyperintense nodes on T2-weighted images. Parathyroidectomy yields excellent results, enabling conservative management of lytic lesions.