One hundred thirty-two of 397 consecutive percutaneous fine needle aspirations done at the University of Virginia between January, 1979, and December, 1984, for pulmonary lesions showed no evidence of cancer on cytological examination. We reviewed the presenting symptoms, radiographic findings on the day of needle aspiration, and the descriptive cytological terms to determine if it was possible to distinguish benign from malignant disease in these 132 patients. We found a specific benign diagnosis in only 16 (12%) of the 132 patients, and 1 of them ultimately was found to have cancer. In the remaining 116 patients, analysis of age, sex, smoking history, presenting symptoms, radiographic findings at the time of needle aspiration, and cytological terms other than malignancy did not enable distinction of benign from malignant disease as the cause of the radiographic finding. In the group of 132 patients without suggestion of cancer on initial cytological study, 38 (29%) were subsequently found to have a malignant process.