Lung nodule 3mm may have blood vessel penetration. If the lung nodule is caused by tumor, the diameter of 3mm may have blood vessel perforation, blood vessel perforation will nourish the surrounding cells, need to go to the hospital to do further histocytology or other aspects of the examination, to understand the specific causes of the lung nodule blood vessel perforation. However, not all 3mm lung nodules will have blood vessel penetration, such as ground glass density nodules, which are early stage lung cancers that grow along the alveolar wall, and the imaging features may not cover blood vessels. If the physical examination found 3mm lung nodule, it is recommended to go to the hospital in time for further examination, to clarify the nature of the standardized treatment as prescribed by the doctor.