[Pulmonary nodules].

Solitary pulmonary nodules 3 cm or greater in diameter should be regarded as probably malignant. Single spherical lesions of smaller size are in about 30% primarily bronchogenic carcinomas, in 10% solitary metastatic deposits and in about 60% benign nodules, commonly infectious granulomas. The generally accepted criteria for benignity are the detection of a "benign" pattern of calcification, no growth over the preceding two years, minimal exposure to tobacco, and the age under 30 years. In general, resectable malignant solitary nodules should be identified and removed. Metastatic tumor deposits are the most common cause of multiple nodules.