A CASE OF BENIGN PARAGANGLIOMA WITH TRANSIENT HYPERPARATHYROIDISM

Abstract

INTRODUCTION
The co-existence of phaeochromocytoma with hypercalcemia is attributed to various factors including MEN2 (Multiple Endocrine Neoplasia), catecholaminestimulated bone resorption and PTH secretion by the parathyroid glands, ectopic production of PTH by pheochromocytoma and PTH-related protein (PTHrP). In contrast to other causes, serum PTH is suppressed in PTHrP besides elevated urinary cyclic AMP and detection of PTHrP immunoreactivity in the tumor tissue. Irrespective of the cause, hypercalcaemia resolved in all reported cases after removal of the phaeochromocytoma lesions.

CASE
A 37-year-old Chinese lady with 2 years of hypertension developed hypertensive emergency with intracranial bleeding in 2017. She did not have any paroxysmal symptoms or features of other hereditary syndromes. Work-up for secondary causes of hypertension noted raised 24-hour urine norepinephrines at 290 micrograms. CT adrenals showed a left para-aortic lesion measuring 2.5x1.6x3.7 cm which was confirmed by Gallium 68 PET CT at L3 vertebrae level. She was incidentally noted to have hypercalcaemia with cCa 2.7 mmol/l and iPTH 108.7 pg/ml with normal phosphate, alkaline phosphatase and vitamin D levels. Neck ultrasound and sestamibi scan were negative for parathyroid lesion and abdominal ultrasound didn’t reveal stones. Negative serum calcitonin and CEA ruled out medullary thyroid carcinoma as part of MEN2. However, the calcium and PTH levels normalised within a few months, even before laparoscopic excision of the benign left paraganglioma.

CONCLUSION
The likely reason for hypercalcaemia in this case could be due to stimulation of PTH secretion by the catecholamines which was transient as the hypercalcaemia resolved before removal of phaeochromocytoma.