August 1st 2002ABSTRACT: When a solitary lung nodule is detected, the key question is whether the lesion is malignant. The initial evaluation includes a careful history taking focused on risk factors for malignancy, a thorough physical examination, comparison of current chest films with previous ones, and CT scanning. Radiologic signs that suggest malignancy include lesion size greater than 2 cm in diameter, spiculated margins, lack of calcification, and change in size. Video-assisted thoracoscopic surgery or thoracotomy is the next step for patients with a suspected malignant lesion. If the results of the initial evaluation are equivocal, positron emission tomography (PET) scanning is the preferred follow-up.