Inflammatory Pseudotumor of the Lung

The first case of an inflammatory pseudotumor of the lung recorded at the University of Missouri Medical Center, Columbia, Mo., affords the opportunity to introduce this entity into the radiological literature. This relatively rare condition should not be confused with the so-called “pseudotumor of the lung” which consists of fluid loculated between layers of pleura. Report of a Case An 8-year-old white girl was first seen at the University of Missouri Medical Center on June 30, 1959, for treatment of cardiac failure. An admission chest film showed a greatly enlarged heart and diffuse pulmonary edema (Fig. 1). The patient improved on medical therapy and at subsequent cardiac catheterization, a diagnosis of interventricular septal defect was made. On April 5, 1960, through a median sternotomy, under open heart technic with the heart-lung bypass, the intraventricular septal defect was closed. The patient did well, and roentgenograms obtained July 15, 1960, showed marked decrease in cardiac size and clearing of operative changes (Fig. 2). The child was followed periodically and showed continued diminution in heart size. A chest roentgenogram, Aug. 1, 1962, showed an ovoid soft-tissue density, measuring 4 cm. in diameter in the left lower lobe (Fig. 3). Diagnostic possibilities suggested radiographically were inflammatory granuloma and arteriovenous aneurysm. Tests for febrile agglutinins and skin tests for tuberculosis and histoplasmosis were negative. On exploratory thoracotomy, Sept. 25, 1962, a firm mass was found in the superior segment of the left lower lobe, and the lobe was resected. Examination of the resected tissue showed a soft, ovoid, well circumscribed mass that measured 3.5 cm. in its greatest diameter. Surrounding lung parenchyma was compressed and separated from the mass without difficulty. Major bronchi were not in close proximity. The surface of the tumor was smooth, slightly bosselated, and pale yellow. The histologic picture was one primarily of a loose stroma of fibroblasts and small vascular spaces diffusely infiltrated with plasma cells and lymphocytes (Fig. 4). In most areas, plasma cells predominated. There were microscopic extensions of the infiltrate into the surrounding lung parenchyma. Cultures of the tumor were sterile.