From Secondary Hyperparathyroidism to Neurologic Crisis: A Tale of Brown Tumor and Spinal Cord Compression

A 26-year-old male with medical history of polycystic kidney disease, IgA nephropathy, end-stage renal disease, and brown tumor (requiring prior surgical intervention on brown tumor) was hospitalized because of right lower extremity weakness. Examination revealed right hip flexor weakness and right foot clonus. Laboratory results showed serum calcium of 10.4 mg/dL (2.59 mmol/L) (reference range: 8.5-10.5 mg/dL; 2.12-2.62 mmol/L). Magnetic resonance imaging displayed a 2.5 × 3.7 cm soft tissue mass with circumferential encroachment of the epidural space leading to severe spinal canal stenosis of T4-T5 at the site of prior brown tumor resection. The patient underwent subtotal parathyroidectomy with left cervical thymectomy, leading to an intraoperative PTH drop from >3500 pg/mL (>371 pmol/L) (reference range: 12-88 pg/mL; 1.27-9.33 pmol/L) to 247 pg/mL (26.182 pmol/L). In the context of treating vertebral brown tumors, the consensus suggests that parathyroidectomy plays a crucial role in achieving both clinical and radiographical amelioration of the tumor. However, in cases like ours where paresis is present, surgical decompression of the tumor becomes imperative. The development of brown tumors is an uncommon and severe, long-term complication for hyperparathyroidism. The location of a brown tumor in the thoracic spine causing symptomatic cord compression is rare.