Brown Tumor with Multiple Lesions as a Manifestation of Tertiary Hyperparathyroidism: A Case Report and Literature Review

Brown tumor is an uncommon focal lytic bone lesion, which is considered as an end-stage lesion of abnormal bone metabolism, caused by long-standing increased parathyroid hormone levels. It is a rare manifestation of hyperparathyroidism that is classified into three types, of which tertiary is the rarest. It can be found in any part of the skeleton, and in some cases, occurs in multiple bones and can be easily misdiagnosed as a metastatic tumor. Therefore, although uncommon, it should be generally considered as a differential diagnosis with bone malignancy lesions, and particularly in patients with renal failure on long-term hemodialysis. In the present case report, a young patient with end stage renal disease presented with tertiary hyperparathyroidism revealed by multiple brown tumors of the pelvis and mandible. We recall through this observation the importance of clinical context, the complementary roles that different imaging modalities can play in different settings, and the relevance of measuring serum calcium and parathyroid hormone before the diagnosis of osteolytic bone lesions.