Multidisciplinary approach to atypical parathyroid tumours and severe hypercalcemia: a case report

Atypical parathyroid tumours (APTs) are a recently classified parathyroid neoplasm with uncertain malignant potential that necessitates cautious management and surveillance. Little data exists regarding clinical and biochemical manifestations of APTs and their delineation from other parathyroid neoplasms, especially parathyroid carcinomas. This case report provides further data in the form of clinical features and perioperative parathyroid hormone trends to increase the understanding of factors that can inform the differential diagnosis of parathyroid neoplasms. This case also highlights the role of multidisciplinary management of APTs and ongoing surveillance in the context of ongoing primary hyperparathyroidism (PHPT) post-resection.

Our case describes a 66-year-old Caucasian male with an exacerbation of chronic obstructive pulmonary disease due to infection, and an incidental finding of severe hypercalcaemia and PHPT. This prompted further investigations that identified a parathyroid neoplasm with clinical and biochemical features most concerning for parathyroid carcinoma, however, it was found to be an APT. A multidisciplinary approach was utilised during pre- and post-operative management to normalise serum calcium levels, surgically resect the APT, and for ongoing surveillance that subsequently identified a parathyroid adenoma.

APTs and parathyroid carcinomas are challenging entities to delineate in the assessment and management of PHPT. A multidisciplinary approach is crucial to manage severe hypercalcaemia secondary to APTs, as is ongoing surveillance postoperatively, given the potential for multiglandular causes of PHPT. Biochemical differences between APTs and parathyroid carcinomas require further research, although perioperative PTH trends may be useful in differentiating APTs and parathyroid carcinomas prior to resection, and immunohistochemical markers may aid histological differentiation.