Differentiation of acute hyperparathyroidism from severe hypercalcemia of malignancy

Acute hyperparathyroidism should be distinguished from severe hypercalcemia of malignancy. In the former condition parathyroidectomy is often of vital importance; in the latter, the malignant neoplasm should be treated surgically or with radiation or cytostatics. The differential diagnosis is sometimes difficult because some patients with acute hyperparathyroidism have coexisting carcinoma elsewhere. Two patients subjected to parathyroidectomy because of severe hypercalcemia secondary to malignant neoplasms are described and compared with twelve similar cases from the literature. In patients with severe hypercalcemia medical treatment should always be tried first. If acute hyperparathyroidism cannot be excluded, subtotal parathyroidectomy should be performed after medical preparation.