PMC3937127_01
Chest HRCT scan and gross examination of the lungs. (A) HRCT scan: nodular shadows were distributed in a centrilobular fashion, often extending to small branching linear areas of attenuation ("tree-in-bud" pattern); (B-D) gross examination of the lungs showed bilateral multiple white-yellowish small nodules centred on small airways.
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PCR detection of most common respiratory viruses (including HTLV-1) were negative. A chest High Resolution Computed Tomography (HRCT)-scan showed mild bilateral dilatation of airways, bronchial wall thickening and a centrilobular distribution of nodular shadows, often extending to small, branching linear areas of attenuation ("tree-in-bud" pattern), predominantly in the middle and upper fields, consistent with bronchiolitis (Figure 1A). Panlobular emphysema was present in the lower lobes. At gross examination, the lungs showed multiple bilateral white-yellowish small nodules, 2-5 mm in diameter, centred on small airways, more frequently in the upper lobes, associated with bronchiectases (Figure 1B-D).
Histological features. (A-D) Transmural and peribronchial infiltration by lymphoctytes and histiocytes was found, with prominent and diffuse involvement of respiratory and terminal bronchioles; most of the histiocytes were foamy macrophages, which formed "nodules", distributed especially in the wall of respiratory bronchioles, in the surrounding interalveolar septa and around the blood and lymphatic vessels. HE, x25. (E) The inflammatory infiltrate showed a characteristic topography: the bronchiolar lumen contained neutrophils, while the peribronchiolar infiltrate was constituted of an inner layer of lymphocytes and an outer layer of histiocytes. HE, x200. (F) Note the exuberant perivascular distribution of foamy macrophages. HE, x200.
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A severe peribronchial and peribronchiolar fibrosis was also seen (Figure 2A-F).
Immunohistochemical stains. (A-B) CD20+ B-cells were almost absent in the lymphocytic infiltrate; (C-D) a heterogeneous population of CD4+ and CD8+ T-cells was present.
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T-cells in the lymphocytic infiltrate (Figure 3C-D).