Primary hyperparathyroidism presenting as a brown tumor with hypercalcemia crisis in a second-trimester pregnant woman: A case report

INTRODUCTION: Primary hyperparathyroidism (PHPT) in pregnancy is rare and unrecognized because the maternal physiological adaptations blurs the symptoms. There is no standard treatment strategy for maternal PHPT. Early diagnosis and interventions can prevent catastrophic consequences to the mother and fetus. PATIENT CONCERNS: A 31-year-old Chinese woman was admitted, due to a lump on the left lower leg for 4 months. The patient complained of mild pain in the left lower leg following exercise that could be relieved after a short rest. The patient was at 18 weeks of gestation, and the growth of the fetus was normal. The patient has a 3-year history of hypercalcemia and a 2-year history of nephrolithiasis. No family history of hypercalcemia and endocrine tumors were present. DIAGNOSIS: Laboratory tests demonstrated high serum calcium level of 3.84 mmol/L, parathyroid hormone 1393 pg/mL, alkaline phosphatase 488 μ/L. Ultrasound showed a 22.4 mm × 7.8 mm solid nodule in the left lower lobe of the thyroid gland. Based on these findings, the patient was diagnosed with PHPT. INTERVENTIONS: The patient accepted continuous renal replacement to reduce ironized calcium level. Parathyroidectomy was performed at the 19th week of gestation. Threatened abortion occurred 2 days after the surgery, and magnesium sulfate was used to prevent the abortion. Calcium gluconate, calcium carbonate and vitamin D3 were used to treat the hypocalcemia that occurred 5 days after the surgery. OUTCOMES: Pathology examination demonstrated the parathyroid adenoma. Abortion was prevented using magnesium sulfate and hypocalcemia was cured with calcium gluconate, calcium carbonate and vitamin D3. At 38-week of gestation, the patient (ionized calcium level: 2.16 mmol/L) delivered a healthy female baby weighing 2700 g with 10/10 Apgar. Till now, both the mother and infant showed no complications. CONCLUSION: Maternal PHPT is rare and challenging to diagnose, causing life-threatening complications to mother and fetus. Any decision regarding surgery for a pregnant woman with primary hyperparathyroidism is more complex than in men or nonpregnant women. The decision should be made based on the severity of hypercalcemia and symptoms.