The unit of lung nodule 11cm should be mm, its seriousness is related to the pathological nature of the nodule and whether the treatment is carried out, etc. Lung infection is generally not serious, and due to tumor is more serious. 1. Relatively not serious: if the lung nodule is caused by the accumulation of exudate mechanization due to lung infection, this situation will not be particularly serious as long as it is treated with regular anti-infection therapy, you can take cephalosporin and other antibiotics under the guidance of the doctor for anti-inflammatory and anti-tuberculosis treatment, and regular re-examination. 2. Relatively serious: If the lung nodules are caused by tumor, the nodules may be accompanied by uneven internal density, burrs and vacuoles on the edges and other signs. Once diagnosed as tumor disease, it is generally more serious. However, with early detection and appropriate treatment, a relatively good prognosis can be achieved. It is important to note that when lung nodules are found, they should be actively consulted under the guidance of a doctor to avoid delays.