Background
The most common presentation of Primary hyperparathyroidism (PHPT) is asymptomatic hypercalcaemia. Parathyroid hormone (PTH) levels are generally mildly elevated or inappropriately normal given the hypercalcaemia. Parathyroid carcinoma, in contrast presents with severe hypercalcaemia and PTH elevation between 3 and 10 times of the normal ranges1. Metabolic bone and renal complications are more common.
We describe 2 cases of profound hyperparathyroidism (HPT), suspicious for parathyroid carcinoma with varying clinical and biochemical complications.
Case 1
K.K, a 55-year-old female referred for elevated Alkaline Phosphatase (ALP) of 627U/L (RR:40-120U/L)+, with corrected calcium (cCa) of 2.72mmol/L (RR:2.15–2.50mmol/L)*, hypophosphatemia of 0.6mmol/L (RR:0.8-1.4mmol/L)~, markedly raised intact PTH (iPTH) of 182pmol/L (RR:0.8-6.8pmol/L)^ and Vitamin D of 9ug/L (RR:20-50ug/L)#. Bone mineral densitometry (BMD) revealed severe osteoporosis. Thyroid ultrasound (TUS) and MRI neck showed a left parathyroid mass of 3.6x0.6x1.4cm with features suspicious for oesophageal wall involvement.
Hypercalcaemia remained stable with oral hydration. K.K underwent parathyroidectomy 2 months later.
Case 2
J.S, a 40-year-old female with 4-year history of recurrent renal calculi, was referred for severe hypercalcaemia of 3.34mmol/L* and iPTH of 150pmol/L^, phosphate of 0.5mmol/L~, and vitamin D of 17ug/L#. ALP was 125U/L+. TUS showed a 4.8cm well-circumscribed parathyroid nodule. BMD revealed osteopenia.
Hypercalcaemia was managed inpatient with intensive intravenous fluids, Calcitonin, Bisphosphonate and Cinacalcet. A transient improvement was achieved with a nadir cCa of 2.7mmol/L*, which subsequently rise within days to a peak of 3.22mmol/L*. Inpatient parathyroidectomy was performed.
In both cases, no hypocalcaemia or hungry bone syndrome was evident post operatively. Histologies were consistent with parathyroid adenoma.
Conclusion