CT findings in lymphangitic carcinomatosis
of the lung: correlation with histologic findings and pulmonary function tests.
The most common cause of the linear pattern is hydrostatic pulmonary edema (Figure 1), but other etiologies include lymphangitic carcinomatosis (Figure 2), and atypical interstitial pneumonias such as those caused by mycoplasma, chlamydia, cytomegalovirus (CMV), and respiratory syncytial virus (RSV).
Lymphangitic carcinomatosis may cause either beaded or smooth septal thickening.
Although clinical manifestation of microscopic tumor embolism and lymphangitic carcinomatosis is similar, cor pulmonale and hemorrhagic infarcts are seen more commonly in microscopic tumor embolism.
Patients with microscopic tumor embolism have clear lung fields on lung radiographs as compared with the interstitial pattern of lymphangitic carcinomatosis, (1) and ventilation-perfusion scan may show multiple subsegmental peripheral perfusion defects described as "segmental contour pattern.