PMC10448582_01
High-resolution chest CT showing a wedge-shaped density extending from the hilum anteriorly and inferiorly towards the chest wall, confirming the presence of middle lobe syndrome [red arrow in (A), axial view, and (B), sagittal view]. Coronal view (C) shows polypoid-like neoformation of the anterior wall of the left common bronchus (red arrowhead), confirmed in axial view (D, red arrowhead). High-resolution chest CT performed 15 days after the bronchodilation procedure documented regression of the middle lobe atelectasis (E, axial view).
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ML bronchial branch ( Figures 1A, B ). Moreover, diffuse thickening of the proximal bronchial walls of the inferior ipsilateral lobar branch, the common bronchus of the left lobe, and the origin of the bronchial branches of the lingula were detected. A polypoid-like neoformation of the anterior wall of the left common bronchus was reported as well, measuring approximately 8 x 10 mm ( Figures 1C, D ). At follow-up chest CT scan, reventilation of middle lobe was documented ( Figure 1E ).
On bronchoscopy, the right main bronchus was partially obstructed by fibrotic stenosis (A). (B) shows bronchoscopic images after dilatation and 1 month later showing complete healing of bronchial tear (C).
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After fiberoptic bronchoscopy (FOB), stenosis at the origin of the middle lobar bronchus, associated with architectural stenosis of the distal section of the left main bronchus, was confirmed ( Figure 2A ). Because of lack of response to conservative treatment, endoscopic attempt of middle lobar bronchus dilatation (by Fogarty 4 F balloon and tissue removal using flexible biopsy forceps) was scheduled ( Figure 2B ). Repeated FOB confirmed improving middle lobar bronchus stenosis ( Figure 2C ).
Microscopic examination revealed: (A) low magnification and (B) high magnification of hematoxylin and eosin staining, showing plasma cell infiltrate in the absence of eosinophils and vasculitis. Since main differential diagnosis includes lymphoma, kappa and lambda light chain immunostains were needed. Immunoglobulin free light chain (IgLC) levels in lung tissue were determined by immunohistochemistry, and no abnormalities were observed both at (C) low and (D) high magnification.
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Bronchial biopsies showed the prevalence of an infiltrate of plasma cells and neutrophils, with isolated eosinophils, in the absence of granuloma, fibrinoid necrosis, eosinophilic vasculitis, and neoplastic cells ( Figure 3 ).