An Interesting Case of Life-Threatening Hypercalcemia Secondary to Atypical Parathyroid Adenoma versus Parathyroid Carcinoma

Context. Severe hypercalcemia is a life-threatening condition. Atypical parathyroid adenoma and parathyroid carcinomas are uncommon causes which can be difficult to differentiate. Objective. We report a case of a 36-year-old male with very high serum calcium due to a possible atypical parathyroid adenoma versus parathyroid carcinoma. Case Illustration. A serum calcium level of 23.2 mg/dl was noted on admission. He was initially treated with IV hydration, pamidronate, and salmon calcitonin to lower his calcium levels. He also underwent a surgical en bloc resection of parathyroid mass. Pathology showed a mixed picture consistent with possible atypical adenoma versus parathyroid carcinoma. However, due to the possible involvement of the recurrent laryngeal nerve, parathyroid carcinoma was more likely. Also after operation the patient developed hungry bones syndrome and his calcium was replaced vigorously. He continues to be on calcium, vitamin D, and calcitriol supplementation. Results. A review of the literature was conducted to identify previous studies pertaining to parathyroid adenomas and parathyroid cancer. Conclusion. We thereby conclude that hypercalcemia requires very careful monitoring especially after operation. Also it can be very difficult to distinguish between atypical parathyroid adenomas and parathyroid carcinomas as in our case and no clear cut guidelines yet exist to differentiate the two based on histology.