Endocrine Abstracts

Introduction: Parathyroid carcinoma is an uncommon cause of primary hyperparathyroidism. It is responsible of 0.4% to 5% of all cases of primary hyperparathyroidism. Parathyroid carcinoma has a high probability of local recurrence, regional node and distant metastasis and the preoperative diagnosis is challenging.

Case presentation: We report a case of a 66-year-old female patient with medical history of hypertension and chronic kidney failure. She was diagnosed with primary hyperparathyroidism and underwent cervicotomy for an ectopic suprasternal and a right paratracheal parathyroid nodule and histopathology confirmed the diagnosis of parathyroid hyperplasia. One year later, she consulted for persistent hyperparathyroidism with malignant hypercalcemia. Sestamibi parathyroid scintigraphy confirmed hyperfunctioning parathyroid tissue in the right thyroid bed and in the mediastinal area. The cervical MRI revealed an ectopic mediastinal nodule of 11.8 mm. Multiple endocrine neoplasia was excluded. The patient underwent surgical removal of the lower right parathyroid and the mediastinal nodule and histological examination of the specimen confirmed the diagnosis of parathyroid carcinoma with clear cell and on-cocytic features. Postoperative calcium and parathyroid blood levels remained high. The presence of pulmonary metastasis was confirmed after practicing a total body scintigraphy and the patient was referred to oncology for chemotherapy.

Conclusion: Parathyroid carcinoma is a rare tumor. The severity of this pathology is due to the severe hypercalcemia aggravating the mortality and to the risk of local recurrence and distant metastases justifying the prolonged monitoring to improve the prognosis of the disease.