Pulmonary inflammatory pseudotumor: radiologic features.

To define the radiologic features of pulmonary inflammatory pseudotumor.Between 1966 and 1994, 61 cases of pulmonary inflammatory pseudotumor involved 36 male and 25 female patients (age range, 17 months to 61 years; mean, 28 years). Clinical presentation, pathologic features, and radiologic findings were noted.At radiography, 52 patients had solitary peripheral nodules or masses, and extraparenchymal involvement--including hilar, mediastinal, and airway invasion--was found in 11. At computed tomography, 12 lesions were of heterogeneous attenuation and five, homogeneous. At T1-weighted magnetic resonance imaging, five lesions had intermediate signal intensity; of two lesions studied with T2-weighted imaging, two had high signal intensity; and the one lesion studied with gadolinium-enhanced imaging had diffuse enhancement.Pulmonary inflammatory pseudotumor was typically a solitary, peripheral, sharply circumscribed mass with an anatomic bias for the lower lobes. Local invasion and primary involvement of the mediastinum and hilar structures were unusual manifestations.