Diagnostic CT features of pulmonary inflammatory pseudotumor

Objective: To study the CT diagnostic characteristics of pulmonary inflammatory pseudotumor. Methods: CT scans of 32 patients with histologically confirmed pulmonary inflammatory pseudotumors were analyzed retrospectively and compared with pathological findings. Results: All 32 lesions were solitary with 28 (87.5%) located near the pleura. 15 presented as round or oval masses and 8 lesions were wedge- or triangular-shaped. There were air bronchogram (4), vacuoles (4), multiple small cavities (3), and necrosis (3). No calcification was found in any of the lesions. Contrast enhancement was marked and uniform (3), marked and heterogeneous (4), moderate and heterogeneous (10), mild and heterogeneous (8). The margins were spiculated (12), peach-tip (3), smooth regular (2), or associated with a halo (3) and converging blood vessels (4). Other findings included adjacent pleural thickening (5), mediastinal lymphadenopathy (1) and pleural effusion (2). Of all 32 cases, 10 (31.6%) were correctly diagnosed on CT, 17 (53.1%) were misdiagnosed as lung cancer, 4 (12.5%) were misdiagnosed as tuberculomas, 1 (3.1%) was misdiagnosed as Wegener granulomatosis. Conclusion: Comprehensive analysis of characteristic CT findings combined with clinical history can improve diagnostic accuracy of inflammatory pseudotumor. (authors)