A case series on parathyroid carcinoma: Diagnostic challenges and therapeutic approaches

Introduction: Parathyroid carcinoma is an exceptionally rare endocrine malignancy, constituting <1 % of primary hyperparathyroidism (PHPT) cases. It presents with more severe hypercalcemia and higher PTH levels than benign parathyroid diseases, requiring increased clinical awareness for accurate identification and specialized management. The results of this case series may provide insight into the clinical presentation, diagnostic workup, surgical management, and prognosis of parathyroid carcinoma, supplemented by a comprehensive review of current diagnostic and therapeutic approaches. Methods: We retrospectively reviewed three cases of parathyroid carcinoma treated at a tertiary referral hospital. We analyzed patient demographics, clinical presentation, imaging studies, surgical interventions, histopathological findings, and follow-up data. We emphasized intraoperative decisions, criteria for achieving sustained hormonal control, and long-term monitoring protocols. Results: Patient 1: An 84-year-old male patient presented with severe hypercalcemia and elevated PTH levels. Preoperative imaging, including 4D CT and sestamibi scan, identified a 3.7 cm, 9.32-gram parathyroid mass, which was surgically resected. Despite removing the mass and normalizing calcium levels, PTH levels remained elevated, suggesting residual disease. Patient 2: A 77-year-old male patient with osteoporosis and a history of kidney stones underwent presurgical parathyroid scintigraphy, which indicated a right superior parathyroid adenoma. A 3 cm, 3.55-gram parathyroid carcinoma was successfully removed, normalizing calcium and PTH levels. Follow-up imaging and labs confirmed no recurrence. Patient 3: A 61-year-old female patient with end-stage renal disease presented with a 5 cm hypervascular neck mass. Preoperative 4D CT and ultrasound suggested an adenoma. After surgery, PTH levels normalized, but the patient died five years later from an unrelated stroke. Conclusion: Parathyroid carcinoma is a rare malignancy that demands thorough diagnostic procedures, imaging techniques, precise surgical intervention, and vigilant long-term follow-up to manage the risk of recurrence. Elevated PTH and calcium levels should raise suspicion of malignancy, especially in severe hypercalcemia. This case series illustrates how the disease can present variably, with unique challenges in each patient. Despite the limitations of current adjuvant therapies, advancements in genetic and molecular research hold promise for future therapeutic options.