Myofibroblastic inflammatory tumor of the lung: CT findings with pathologic correlation.

The objective of this study was to describe the computed tomographic (CT) features of myofibroblastic inflammatory tumor of the lung with histopathologic correlation. The medical records and imaging studies of eight patients with pathologically proven myofibroblastic inflammatory tumor of the lung were reviewed. On radiographs and CT images, a poorly circumscribed mass or nodule was evident in five patients (six lesions), and a well-circumscribed lesion was evident in three patients (three lesions). Seven lesions were peripheral and two were centrally located. At CT, five lesions were of heterogeneous attenuation and four homogeneous. Increased perilesional parenchymal abnormalities, which were caused by peribronchial inflammatory infiltrates, were observed in three cases. The predominant histopathologic feature was organizing pneumonia type in three cases, lymphoplasmacytic type in three cases, and both organizing pneumonia and lymphoplasmacytic type in two cases. Variable degree of fibrous histiocytoma type was observed in all cases. The imaging characteristics of myofibroblastic inflammatory tumor of the lung are variable and nonspecific. The authors conclude that most cases appear as solitary, peripheral lesions with a predilection for the lower lobes. Associated findings may include perilesional inflammatory changes. Because myofibroblastic inflammatory tumor cannot be reliably differentiated from other pulmonary lesions based solely on the imaging appearance diagnostic biopsy is mandatory. Interpretation of the imaging findings combined with the histopathologic features of disease may help make correct diagnosis.