The discovery of a lung nodule after lung cancer surgery could be a sign of recurrence, but it might also be due to an infection such as tuberculosis or the development of a benign lung tumor.

If the nodule discovered after lung cancer surgery is malignant, it is generally considered to be caused by recurrence or metastasis of the lung cancer disease. In such cases, the lung nodules can be solitary or multiple.

Some lung cancer patients may develop inflammatory nodules or tuberculomas in the lungs due to infections caused by pathogens like Mycobacterium tuberculosis, as their immune systems are weakened post-surgery. These nodules usually resolve after anti-inflammatory or anti-tuberculosis treatment.

Additionally, some lung cancer patients may develop benign tumors, such as hamartomas, in their lungs after surgery, which also present as lung nodules. A pathological examination of the nodules can provide a clear diagnosis.

If lung nodules are detected again after lung cancer surgery, it is generally recommended to seek medical attention promptly and follow the standardized diagnosis and treatment provided by a professional doctor.