A NEW ROENTGEN SIGN OF MALIGNANCY IN THE SOLITARY PULMONARY NODULE

The increasing frequency with which isolated rounded shadows, often called coin lesions, are observed in roentgenograms of the lungs presents an extremely difficult problem in differential diagnosis. The literature is replete with descriptions of these spheroidal nodules, their gross and microscopic anatomy, roentgen findings, and clinical significance. Some 30 conditions have been cited as producing such shadows. Most of the contributions indicate that surgical excision with microscopic examination of the tissue is the only safe method for handling such lesions, particularly in patients in the older age groups. But the finding of such a shadow during the course of a survey examination in an apparently healthy person is becoming so common that it is frequently difficult to insist on surgical exploration in every case. Efforts to make a differential roentgenologic diagnosis have not been highly successful. The demonstration of a round, sharply defined contour or the presence of calcium, both