Hypercalcemia in small cell (oat cell) carcinoma of the lung. Coincident parathyroid adenoma in one case.

Hypercalcemia is very uncommon in small cell (oat cell) carcinoma of the lung. Two cases of this neoplasm associated with symptomatic hypercalcemia are described. Despite normal skeletal roentgenograms, metastatic bone disease was demonstrated by abnormal bone scans and bone biopsies in both patients. The combination of conventional antihypercalcemia therapy, cytotoxic cancer chemotherapy, and synthetic salmon calcitonin corrected the hypercalcemia despite progression of the small cell carcinoma. One patient with elevated serum immunoreactive parathyroid hormone (PTH) had a parathyroid adenoma at autopsy. This association emphasizes that in cases of bronchogenic small cell carcinoma with hypercalcemia, conincidental primary hyperparathyroidism should be considered.