Large retrosternal parathyroid carcinoma with primary hyperparathyroidism.

Parathyroid carcinoma is an uncommon cause of parathyroid hormone (PTH)-dependent hypercalcaemia, accounting for less than 1% of all cases of hyperparathyroidism. Parathyroid carcinoma is an indolent tumour with rather low malignant potential. Consideration of parathyroid carcinoma in the differential diagnosis of hypercalcaemic disorders is important because the morbidity and mortality are substantial and the best prognosis is associated with early recognition and surgical resection. Clinical indicators favouring parathyroid carcinoma over benign disease include markedly raised serum calcium levels, PTH and alkaline phosphatase. A palpable neck mass with both kidney and skeletal manifestations also give a high index of suspicion of parathyroid carcinoma. Histopathology alone is not sufficient to diagnose parathyroid cancer; it has to be correlated with the clinical findings. The initial and most effective treatment for parathyroid carcinoma is complete resection of the primary lesion, and repeated operations for recurrence are useful. The prognosis of parathyroid carcinomas is quite variable; 5-year survival rates vary from 40% to 86%, while the 10-year survival rate is approximately 49%. We report a case of parathyroid carcinoma occurring in a 55-year-old woman who presented with bone pain and hypercalcaemia.