Abstract： Parathyroid carcinoma (PC) is a rare neoplasm that accounts for 0.1％-5％ of primary hyperparathyroidism cases.HyperparathyroidiSm-induced hypercalcemic crisis (HHC) is sometimes due to a single PC.1 However,due to a lack of definitive diagnostic markers and overlapping clinical features of this condition with adenomas,it has been difficult to diagnose.2 In this report,we investigated the preoperative management,clinical presentation,surgical management,histopathological findings,and outcomes of six patients that presented with PC initiated by HCC.The aim of the retrospective study was to elucidate clinical patterns that may facilitate a diagnosis of PC.