Parathyroid Carcinomas: A Series of 6 Cases and Literature Review

Parathyroid carcinoma (PC) is a rare endocrine malignancy. We report 6 cases of PCs operated on in our department, during a period of 12 years (2010-2021). All of our patients presented severe hyperparathyroidism, high calcium levels, and very elevated parathormone (PTH) rates. Five were between the fifth and sixth decades of life and 1 patient was 37 years old. The parathyroid gland was only palpable in 1 case. All of our patients underwent cervical ultrasound and 5 of them underwent 99m Tc-MIBI scintigraphy. One of the patients presented bilateral parathyroid masses. All our patients were treated surgically: a parathyroidectomy was performed in all cases. In 1 patient, parathyroidectomy was performed in conjunction with a homolateral loboisthmectomy, as the diagnosis of PC was suspected preoperatively due to pulmonary metastases. The final anatomopathological study revealed PC in all cases. Follow-up was uneventful in 5 cases and 1 patient was lost to follow-up. Clinicians should suspect PC in patients with severe hypercalcemia, extremely elevated PTH levels, large parathyroid lesions, and distant metastases. Complete surgical resection, extended to the homolateral thyroid lobe, remains the recommended treatment.