Brown Tumor With Spine Involvement at Multiple Levels in a Hemodialysis Patient.

Brown tumor of the bone or osteitis fibrosa cystica is a rare manifestation of hyperparathyroidism, most seen nowadays in association with secondary and tertiary hyperparathyroidism. Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are the major culprits of secondary hyperparathyroidism (sHPTH). CKD is known to cause phosphate retention and a decrease in 1,25-dihydroxyvitamin D and ionized calcium levels, which in turn trigger the PTH secretion. Brown tumor can affect the jawbones, femur, sternum, ribs, and rarely the spine. We present the case of a 60-year-old male with ESRD on hemodialysis who was found to have lytic bone lesions in the thoracic and lumbar spine. Initially, malignancy was suspected. Blood work revealed markedly elevated PTH at 3,563 pg/mL, hypocalcemia, and hyperphosphatemia. Biopsy of the L5-S1 lesion was consistent with reactive changes due to sHPTH. Once a diagnosis of the brown tumor was confirmed, the patient was started on cinacalcet and was referred for parathyroidectomy.