Correct!
4. Allergic bronchopulmonary aspergillosis
The tubular nature of the left lower lobe opacities is consistent with bronchiectasis and bronchial impaction. The hyperattenuating nature of the bronchial impaction is highly suggestive of Aspergillus infection, owing to that organism’s ability to fix iron, calcium and manganese ions, which produces increased attenuation on thoracic CT. The focal nature of the bronchiectasis is somewhat peculiar for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA), although focal ABPA presentations have been recognized. Cystic fibrosis is an unlikely diagnosis given the patient’s history and the imaging findings- typically cystic fibrosis produces more widespread bronchiectasis, somewhat favoring the upper lobes, especially the right, and this distribution of abnormalities at thoracic CT is absent in this case. Post-infectious bronchiectasis, worldwide commonly caused by Pertussis and viral infections, such as measles, most often shows bilateral lower lobe predominance and is not typically focal in nature, and does not show a predilection for producing hyperattenuating bronchial impaction. Non-tuberculous mycobacterial infection causes several distinct appearances at thoracic CT, including a post-primary mycobacterial infection appearance (upper lobe consolidation, cavitation, nodules, and bronchiectasis) and the “Lady Windermere” syndrome (right middle lobe and lingular predominant bronchiectasis, consolidation, and nodules with tree-in-bud formation). The typical thoracic CT appearances and demographics associated with these presentations of non-tuberculous mycobacterial infection are absent in this case. Primary ciliary dyskinesia, or immotile cilia syndrome, is often associated with very widespread bronchiectasis and small airway impaction, and typical does not present with focal bronchiectasis. Additionally, small airway abnormalities consistent with bronchiolitis are often far more widespread in patients with primary ciliary dyskinesia than is seen in this case, and often the patient’s history would be more suggestive of recurrent pulmonary infection and other abnormalities. Situs abnormalities are present in Kartagener syndrome, but the patient’s situs is normal in his case.
The patient’s total serum IgE level was elevated (1200 IU/mL), serum Aspergillus fumigatus precipitins and skin testing were positive, and peripheral eosinophilia was present. These features, in combination with the patient’s clinical history and imaging findings, were considered consistent with ABPA. Due to the somewhat unusual focal nature of the disorder, bronchoscopy with bronchoalveolar lavage and transbronchial biopsy was performed, which revealed elevated IgE and eosinophils in the bronchoalveolar lavage fluid, and biopsy recovered airway infiltration by eosinophils, mucoid impaction, and Aspergillus organisms, confirming the diagnosis. No obstructing endobronchial lesion was seen.
Diagnosis: Allergic bronchopulmonary aspergillosis / Allergic bronchopulmonary mycosis
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