Pulmonary nodule
Pulmonary nodules are small, rounded opacities within the pulmonary interstitium. Pulmonary nodules are common and, as the spatial resolution of CT scanners has increased, detection of smaller and smaller nodules has occurred, which are more often an incidental finding.
On this page:
Classification
Pulmonary nodules can be classified according to size, morphology and/or distribution.
Size
- miliary nodules: <2 mm
- pulmonary micronodule: 2-7 mm
- pulmonary nodule: 7-30 mm
- pulmonary mass: >30 mm
Morphology
Distribution
Radiographic features
They are generally homogeneous (without air bronchograms or alveolograms) and are well-defined since their margins are sharp and they are surrounded by normal aerated lung. They are quite separate from airspace nodules that often have an irregular margin and are usually ~8 mm in diameter. (For further discussion, see the article on nodular opacification.)
Differential diagnosis
The differential diagnosis for a nodule can be refined by its size, location, and density. Solitary pulmonary nodules and hyperdense pulmonary nodules are discussed further elsewhere.
A micronodular or miliary pattern is predominately seen in granulomatous processes, haematogenous pulmonary metastases, and pneumoconioses. Nodules and masses are most often seen in metastatic disease to the lung.
Always be aware of artifacts, especially on radiographs, where buttons or nipple shadows can often be mistaken for a true pulmonary nodule 7.
Unable to process the form. Check for errors and try again.