Lung lesions do not always indicate lung cancer, according to MedicineNet.com. For example, a Ghon lesion on the lung is a scar left over from childhood tuberculosis.
Lung lesions are common, and most of them are benign, according to Mayo Clinic. These types of legions are usually small, while large lesions are more likely to be malignant. If a physician is suspicious of a lung lesion, she might compare the patient's most recent chest X-rays with X-rays taken earlier. If the lesion hasn't changed in over two years, it's most likely benign. A lesion that changes over time may require further testing.