Medullary carcinoma of the thyroid with parathyroid adenoma and hypercalcaemia.

A patient with hyperparathyroidism due to a parathyroid adenoma was found to have metastatic medullary carcinoma in lymph nodes close to the thyroid gland. The finding of normal calcitonin and parathormone concentrations after removal of the adenoma suggested that the parathyroid lesion was not the result of the hypocalcaemic action of calcitonin produced by the tumour in the thyroid. Seventeen other examples of the association between medullary carcinoma and parathyroid enlargement are briefly reviewed.The pathogenesis of the parathyroid lesions is discussed, and it is suggested that some may be caused by the hypocalcaemic action of calcitonin, while others may be part of a syndrome of multiple endocrine adenomatosis.