Brown Tumor: An Uncommon Manifestation of Severe Hyperparathyroidism.

Brown tumor is now an uncommon form of osteitis fibrosa cystica. It results from an imbalance in bone remodeling, which leads to osteolytic lesions. This process, marked by microfractures and discoloration, is triggered by persistently elevated parathyroid hormone levels in end-stage renal disease (ESRD) patients with tertiary hyperparathyroidism. Our case highlights a large brown tumor in the maxilla causing significant facial deformity. A 34-year-old female patient with ESRD had multiple admissions to our facility for various reasons. She was non-adherent to her dialysis treatment regimen and medications. She had a facial mass that had doubled in size over a year. Laboratory results showed elevated calcium and phosphorus levels and extremely elevated parathyroid hormone (PTH) levels. A computed tomography (CT) scan showed an exophytic mass arising from the anterior left maxilla, suggestive of a brown tumor. A sestamibi parathyroid scan and neck sonogram did not confirm hyperplastic parathyroid glands. Nevertheless, a biopsy of the mass showed multinucleated giant cells and stromal spindle cells consistent with a brown tumor. The patient would have benefited from a parathyroidectomy, but she refused and signed out against medical advice. Brown tumors are now uncommon in the USA due to effective medical management of bone mineral disorders associated with ESRD and efficient renal replacement therapy. However, our case emphasizes that brown tumors may occur in ESRD patients who do not adhere to their treatment regimen.