Regression of orbital brown tumor after surgical removal of parathyroid adenoma

Brown tumors are rare skeletal manifestations that occur in less than 2% of primary hyperparathyroidism (PHPT) cases. Even rarer is the occurrence of brown tumor of the orbit, and few cases have been reported around the world. The rare instance of this benign tumor has prompted us to report the case and treatment of an orbital brown tumor in a patient with PHPT caused by parathyroid adenoma. We present the case of a patient undergoing follow-up at a referral center. The 60-year-old female patient, presented herself with progressive swelling in the nasal region, epistaxis and proptosis, she had noticed seven months prior to our examination. Multiple imaging and laboratory findings revealed parathyroid hormone (PTH)-dependent hypercalcemia (total calcium = 14.3 mg/dL and PTH = 1,573 pg/mL), a nodular lesion in the upper pole of the left thyroid lobe and increased uptake in left upper cervical region. The patient underwent left superior parathyroidectomy in September 2011, which led to the normalization of hypercalcemia and regression of the orbital tumor, as seen on control CT scan. This case highlights the spontaneous regression of the brown tumor after surgical management of the parathyroid adenoma.