Correct!
2. A congenital pulmonary lesion
The frontal and lateral chest radiograph shows a mass-like process in the medial left lung base. While an uncommon occurrence in general, a congenital pulmonary lesion is the most likely diagnosis among the considerations provided. A community-acquired pneumonia would probably be the most likely consideration in this circumstance overall, but that choice was not included above. Bronchogenic carcinoma is a consideration, but is extremely rare in a non-smoking patient of this age. The lesion shown is probably located in the medial left lower lobe, and not the mediastinum, so mediastinal germ cell neoplasm is not an appropriate choice- that diagnosis is typically encountered in the anterior mediastinum. Similarly, a Morgagni hernia is found in the anterior mediastinum, representing fat extending from the upper abdomen into the thorax, classically described in the right cardiophrenic angle. Pneumocystis jiroveci pneumonia usually is encountered in severely immunocompromised patients, and presents with perihilar or diffuse bilateral ground-glass opacity or linear / interstitial-appearing opacities, not as a focal left lower lobe mass.)
Clinical Course: The patient subsequently underwent thoracic CT (Figures 2B-G) for further characterization of the lesion seen at chest radiography.
Figure 2. Contrast-enhanced thoracic CT, obtained while the patient was clinically infected, in soft tissue (B-F) and lung windows (G) show a lesion in the medial left lung base, abutting the mediastinum. The lesion shows central cavitation. The lesion shows extensive internal vascularity. (click here for a movie of the CT scan)
Regarding the CT appearance of the lesion, which of the following is most accurate?
