Expect the unexpected: Brown tumor of the mandible as the first manifestation of primary hyperparathyroidism

Table 1 Patient’s laboratory examination

Patient’s laboratory values	Normal range
Total calcium level = 2.94 mmol/L	2.14-2.53 mmol/L
Ionised calcium level = 1.61 mmol/L	1.18-1.32 mmol/L
Phosphorus level = 0.66 mmol/L	0.79-1.42 mmol/L
Daily urine calcium level = 11.69 mmol/dU	< 7.9 mmol/dU
PTH level = 44.02 pmol/L	1.59-7.24 pmol/L
25 OH vitamin D level = 27.97 nmol/L
Creatinine level = 66 μmol/L	64-104 μmol/L
Estimated glomerular filtration rate (CKD-EPI formula) = 102.8 mL/min/1.73 m2

PTH: Parathyroid hormone; CKD-EPI: Chronic Kidney Disease Epidemiology Collaboration.