Background
Atypical parathyroid tumours (APT) comprise a set of lesions causing primary hyperparathyroidism (PHPT) with almost identical clinical manifestations to parathyroid carcinomas. Given uncertainty surrounding their malignancy potential, these lesions warrant prompt diagnosis and multidisciplinary management. We present an additional case of APT with resultant primary hyperparathyroidism and severe hypercalcemia.
Results
A 66-year-old Caucasian male was hospitalised with an infective exacerbation of his chronic obstructive pulmonary disease and was incidentally found to have severe hypercalcemia and concurrent hyperparathyroidism. Further workup revealed a sestamibi-avid mass in the inferior pole of the right thyroid lobe which was abutting the thoracic inlet and displacing the oesophagus to the left. The patient was managed in a multidisciplinary setting with endocrine involved in stabilisation of the cardiac membrane with the use of zoledronic acid and calcitonin. The patient was prepared for urgent surgical removal of the tumour prior to the suspected rebound tachyphylaxis with prolonged calcitonin use. The patient was discharged on day 14 with an elevated parathyroid hormone (PTH) concentrations of 34.2 pmol/L at time of discharge.
Discussion
Our case highlighted extremely high PTH levels (181.9 pmol/L) in APT at time of admission. Literature suggests APT PTH levels are higher than parathyroid carcinomas, however this different is statistically non-significant with a lack of case reports published. Despite surgical resection, the PTH remained elevated at 34.2 pmol/L at time of discharge and is likely multifactorial secondary to high bone turnover markers and hungry bone syndrome.
Conclusion
APT and parathyroid carcinomas are both rare yet serious neoplasms that demonstrate similar clinical presentations. Larger trials and further case reports need to be published to assess whether preoperative PTH is a suitable marker to distinguish between these 2 entities. These tumours need to be managed in a tertiary centre in a multidisciplinary format.