Intrapulmonary lymph node, abbreviated as IPLN in English.IPLN is a lymph node that occurs within the lung parenchyma. Its CT manifestations are mainly described in terms of morphology and size, number and density, edge and relationship with pleura, peripheral changes and linear dense shadow. 1. Morphology and size: The morphology of IPLN is varied, which can be round, oval, triangular or irregular polygonal, etc. Among them, triangular or polygonal nodules with smooth edges are more characteristic.The diameter of IPLN is usually <1cm, and the longest diameter of IPLN without metastasis is reported to be about 1.5cm. 2. Number and density: IPLN are common as single, mostly solid nodules with uniform internal density and rarely calcified. 3. Margins and relationship with pleura: Most IPLNs have clear borders and smooth margins, usually without obvious lobulation and burr signs. They are mainly located in the subpleural area, close to the dirty pleura or within 1.0 cm from the pleura, and may be close to the interlobar fissure. 4. Peripheral changes and linear dense shadows: In general, the lung field around the IPLN is relatively clear, with no obvious "satellite foci". In conclusion, on CT images, if there is a polygonal, well-defined solid nodule located under the alveolus, near the interlobar fissure with a diameter of <1.0cm, or under the pleura, accompanied by linear dense shadows, the possibility of IPLN should be highly considered, and a professional physician should be consulted for details.