An intraoperative surprise : occult case of non-functional parathyroid carcinoma

Parathyroid carcinoma (PC) exists in <1% of patients with hyperparathyroidism (Figure 1) and typically presents with a robust constellation of findings that rarely go unnoticed. Mean serum parathyroid hormone (PTH) concentrations are commonly 3-to 10-fold higher than the upper limit of normal with a mean serum calcium concentration that frequently exceeds 14 mg/dL. PCs also tend to metastasize to cervical lymph nodes (30%) which is a distinctly ominous sign when associated with this rare pathology as compared to its benign counterpart, parathyroid adenomas. Non-functioning parathyroid carcinomas (NPC), less than 10% of PCs, are exceptionally rare, and can more closely resemble parathyroid adenoma/hyperplasia on preoperative workup further obscuring diagnosis. This disease represents a unique subset of PCs that are rarely addressed in the literature