THE PROBLEM of the diagnosis and management of the isolated pulmonary nodule has become the subject of recent medical publications. This current interest is primarily due to the opportunity for accurate diagnosis and good prognosis offered by modern techniques of thoracic surgery. Fifteen to 30% of the surgical specimens have been found to be primary malignant lung tumors; 50%, granulomas, and the remainder, benign tumors, metastatic lesions, lung cysts, and miscellaneous lesions.* Attempts to differentiate the benign from the malignant lesion by x-ray and laboratory techniques have, with one exception, been held to be unreliable. This exception has been the x-ray characteristic of the finding of calcification within the nodule. It is generally accepted that "the presence of calcium in a pulmonary shadow is suggestive of a benign lesion"1and "most intrapulmonary nodules containing calcium need not be removed."4 Our object in reporting this case of a malignant