Increased 18F-fluorodeoxyglucose uptake in a brown tumor in a patient with primary hyperparathyroidism.

An 86-year-old female presented with a two-month history of an enlarging, left-sided jaw mass. The mass persisted after a course of antibiotics prescribed by her dentist. A CT scan of the mandible (Fig. 1) and biopsy from an outside hospital demonstrated characteristics consistent with a benign Giant Cell Tumor. The patient was referred to Head and Neck Surgery for resection. Upon presentation to our institution, physical exam revealed a 3.5 cm x 4 cm mass along the left lateral aspect of the mandible that was firm and non-tender. Laboratory evaluation revealed calcium 12.0 mg/dL (N: 8.6-10.3), PTH 368 pg/mL (N: 11-51), creatinine 1.2 mg/dL (N: 0.6-1.3), vitamin D-25 43 ng/mL (N: 20-50), vitamin D-1,25 93.1 (N: 19.9-79.3), and alkaline phosphatase 184 U/L (N: 37-113). Bone densitometry demonstrated osteoporosis with a T-score of -4.1 at the left hip and -5.9 at the right distal radius. Parathyroid sestamibi scintigraphy (Fig. 1) and a neck ultrasound did not demonstrate parathyroid adenoma. Parathyroid 4D-CT Scan (Fig. 1) subsequently revealed a 7 mm left sided nodule inferior to the thyroid consistent with parathyroid adenoma. Patient denied a history of nephrolithiasis, acid reflux, constipation or other symptoms of hypercalcemia. The patient underwent left inferior parathyroidectomy. At the time of surgery, a 650 mg left lower pole parathyroid adenoma was removed. Intraoperative PTH levels decreased from 259 pg/mL to 32 pg/mL. Calcium normalized to 10.1 mg/dL post-operatively. At two months follow-up, calcium remained normal at 9.4 mg/dL with a PTH of 27 pg/mL. Her jaw mass was notably diminished in size.