PMC7266995_01
From left to right: (A) HandE staining let a leukocyte bronchial and peribronchial infiltrate be noticed; (B) HandE staining shows the bronchial walls with epithelial cells fallen into the lumen which appears filled by abundant amorphous eosinophilic material in which leukocytes can be detected; (C) immunohistochemical staining with anti-CD45 reveals peribronchial positivity.
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F1
Other tissue sections showed chronic inflammation, and bronchiolar wall fibrosis primarily restricted to bronchioles (Figure 1).
PMC7266995_02
From left to right: (A) the not significant macroscopic study; (B) histological study; (C) immunohistochemistry shows the positivity to anti-CD45 staining. HandE staining shows considerable thickening of the septal structures due to the presence of abundant cellularity, mainly consisting of plasma cells and small lymphocytes. The alveolar spaces are atelectatic in some fields; in others, they show amorphous eosinophilic material inside. In many fields, bronchial and peribronchial infiltrates, consisting of lymphocytes and plasma cells, cover the bronchial structure itself.
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F2
The histology was characterized by lymphocytic infiltration of the bronchioles (Figure 2).
PMC7266995_03
(A-C) Immunohistochemical staining CD45-positive showing peribronchial and intrabronchial wall leukocyte infiltrates.
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F3
At histological examination, focal edema and diffuse congestion of both lungs, acute emphysema, and peribronchial and intrabronchial wall leukocyte infiltrates were found; the same results involved nearby septal vessels (Figure 3).