A patient with CKD complicated by secondary hyperparathyroidism and parathyroid carcinoma: a case report.

Background: Parathyroid carcinoma (PC) is a rare malignancy, representing approximately 0.005% of all malignant tumors. Currently, its etiopathogenesis, diagnostic criteria, and optimal management strategies remain poorly defined. Furthermore, the occurrence of PC in the context of secondary hyperparathyroidism (SHPT) is an infrequent clinical event. This report details a case of PC arising in a patient with chronic kidney disease (CKD) and SHPT. Case presentation: A 53-year-old male with severe renal failure was admitted for clinical evaluation. During the course of hospitalization, SHPT and PC were diagnosed based on clinical, biochemical, and imaging evaluations. Intraoperative pathological assessment confirmed the malignancy, necessitating radical resection with regional lymph node dissection. The patient has achieved a long term disease free survival exceeding 8 years after surgery. Conclusion: The diagnosis of PC remains clinically challenging due to its rarity and the significant overlap in biochemical and imaging features with benign parathyroid lesions. This diagnostic challenge is further intensified in patients with severe renal insufficiency, as characteristic clinical indicators are often masked by comorbid secondary hyperparathyroidism. This report illustrates the diagnostic process and successful long-term management of PC in this challenging context, providing a clinical reference for the standardized treatment of this rare malignancy.