Some anatomical variants and pitfalls in computed tomography of the trachea and mainstem bronchi. I. Mucoid pseudotumors.

472 computed tomographic (CT) examinations in 448 patients were reviewed for mucoid pseudotumors. In 10 patients (2%), an intraluminal density was indirectly proven to be mucous material by negative bronchoscopy and/or repeat CT. Mucoid pseudotumors can easily be differentiated from CT artifacts and from intraluminal neoplasms with extraluminal extension. Differentiation from true intraluminal neoplasmata may be difficult. No definite diagnostic criteria can be proposed since there were no true intraluminal neoplasms present in this series. Nonetheless, several characteristic radiological features of mucoid pseudotumors are discussed. When a potential mucoid pseudotumor is found in a CT examination either the CT scans in question should be repeated after vigorous coughing or an intraluminal neoplasm should be excluded by bronchoscopy. Starting from the CT examination, in the case of bronchogenic carcinoma of the central airways, the intraluminal extent of the tumor might be overestimated due to mucous material proximal to the tumor.