Case report: cholangiocarcinoma and hypercalcemia.

Hypercalcemia is a relatively common problem seen in the presence of malignancy, and is the most common life-threatening metabolic disorder in patients with cancer. In the hospitalized patient, malignancy is the most common cause of hypercalcemia. It is estimated that hypercalcemia occurs in 10% to 20% of patients with cancer. Usually, it is a sign of advanced disease. Approximately 85% of patients with cancer and hypercalcemia will have disease metastatic to bone. The remaining 15%, however, will have some other etiology for their hypercalcemia, typically squamous carcinomas of the head and neck, esophagus, and lung. This type of hypercalcemia has been termed humoral hypercalcemia of malignancy and has been associated with the secretion of various cytokines, including parathyroid hormone-related protein. In this case report, the authors document the production of parathyroid hormone-related protein by an adenocarcinoma-cholangiocarcinoma. This is documented both by measurement of the protein in the patient's serum and staining of the protein within the tumor by a monoclonal antibody. A general discussion of hypercalcemia and malignancy also is provided.