An exceedingly rare localization of a brown tumor in a hemodialysis patient

Secondary Hyperparathyroidism Presenting as a Brown Tumor: A Case Report and Review of the Literature

Severe secondary hyperparathyroidism in advanced stages of chronic kidney disease (CKD) is associated with CKD-related mineral and bone disease (CKD-MBD). A 70-year-old woman was admitted at the Hospital for generalized bone pain and peripheral edema. Initial laboratory tests revealed normocytic anemia and severe renal dysfunction, and further tests evidenced severe secondary hyperparathyroidism. Full-body computerized tomography showed an osteolytic lesion in the right iliac wing. The iliac bone lesion was biopsied and histological examination was consistent with the diagnosis of a brown tumor of hyperparathyroidism. Brown tumors are a rare variant of osteitis fibrosa cystica that results from sustained high levels of parathyroid hormone in CKD. This case sheds light on rare complications that are experienced today in CKD. The clinical and biochemical setting, as well as the clinical suspicion, are essential to the diagnosis.

Multiple Focal Brown Tumors (Osteitis Fibrosa Cystica) in a Renal Transplant Recipient

Brown tumors (BTs) are manifestations of osteitis fibrosa cystica that develops due to increased osteoclast activity secondary to hyperparathyroidism (HPTH). The name comes from its characteristic brown color due to high hemosiderin level and hemorrhage surrounded by osteoclastic giant cells, fibrous tissue, and bone fragments. Presentation can be either unifocal or rarely multifocal. Misdiagnosis of BT compared to malignant giant cell tumor is not uncommon. Early diagnosis and intervention may prevent destructive bone changes. Treatment of BTs due to chronic renal failure should be aimed primarily at its prevention with phosphate binders, vitamin D (analogues), calcimimetics, and prolonged dialysis sessions. Parathyroidectomy can be the option in nonresponsive cases. In this report, we present an unusual case of multiple brown tumors in a 54-year-old female renal transplant patient involving the spine, jaw, and scapula, initially misdiagnosed as giant cell tumor. Five years later, the patient was diagnosed with BT because of the medical history, morphology, and negative p63 staining in combination with secondary/tertiary hyperparathyroidism. The patient subsequently underwent subtotal parathyroidectomy.