Resectable bronchogenic carcinoma presenting with hypercalcemia: tumor-associated granulomatous reaction and probable production of 1,25-dihydroxyvitamin D.

A patient with hypercalcemia, increased levels of 1,25-dihydroxyvitamin D, and a resectable squamous cell bronchogenic carcinoma surrounded by numerous non-caseating epithelioid granulomas, achieved normocalcemia, decreased levels of 1,25-dihydroxyvitamin D, and no evidence of tumor recurrence at 30 months following complete resection of his tumor. We suggest that an excess production of 1,25-dihydroxyvitamin D, through the granulomatous reaction around the tumor, was the mechanism of hypercalcemia. To our knowledge, no such mechanism of hypercalcemia has been previously reported with bronchogenic carcinoma. Furthermore, a review of the literature reveals that in cases of bronchogenic carcinoma, hypercalcemia is almost always associated with large and unresectable tumors, with a median survival after the discovery of hypercalcemia of only one month. This case, then, is unique because it describes an unusual mechanism of hypercalcemia with bronchogenic carcinoma and it emphasizes the rare occurrence of the potentially curable patient presenting with bronchogenic carcinoma complicated by hypercalcemia.