A 58-year-old man with a 700-pack-peryear smoking history presents to the emergency depament with shoness of breath and hemoptysis. Poable chest radiography demonstrates a large mass centrally located within the left lung field. The serum calcium is 13.0 mg/dL (normal 8.5 to 10.2). The metabolic abnormality described here is likely due to elaboration of which substance

The man is likely to have a lung tumor, given his clinical presentation and the radiographic results. The patient's hypercalcemia is likely due to a paraneoplastic syndrome, such as that due to the elaboration of parathyroid-related hormone (PTrH). PTrH is produced by squamous cell carcinoma Adrenocoicotropic-like substance and antidiuretic hormone are produced by yet another form of lung cancer--small cell carcinoma of the lung. Carcinoembryonic antigen is an onco-fetal antigen produced by colon cancer cells. Erythropoietin causes secondary polycythemia and is related to renal cell carcinoma