PMC6010628_01
Chest radiograph shows an irregular opacity in the lower lobe of the right lung (a). Chest computed tomography (CT) scan shows a large area of consolidation with air bronchogram in the right lower lobe and reticular opacities with honeycombing in both lungs (b, c). 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT shows increased uptake (maximum standardized uptake value of 13.03) in the right lung lesion (d).
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Chest radiograph revealed an irregular opacity in the right lower lobe (Fig. 1a). A subsequent chest computed tomography (CT) scan demonstrated a large area of consolidation with air bronchogram in the right lower lobe, and reticular opacities with honeycombing in both lungs (Fig. 1b and c). The right lung lesion showed high uptake (maximum standardized uptake value at 1 hour and 2 hours 9.38 and 13.03, respectively) in the 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT (Fig. 1d).
Cytological findings of the tumor. The smear preparation shows clusters of squamous cells with abnormal keratinization on a hemorrhagic or inflammatory background (a), many clusters of ciliated epithelial cells (arrows), and some portions with columnar epithelium containing mucin (arrowhead) without nuclear atypia (b, c).
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There were many clusters of squamous epithelial cells in a sheet-like or papillary arrangement, and singly scattered cells, including keratinizing cells characterized by thick and deeply eosinophilic cytoplasm on a hemorrhagic or inflammatory background (Fig. 2a). Additionally, there were singly scattered or clusters of ciliated epithelial cells and portions of mucous columnar epithelium without nuclear atypia (Fig. 2b and c).
The macroscopic evaluation of the resected pulmonary specimen shows a solid tumor occupying more than half of the right lobe with variable-sized cystic spaces, together with a honeycomb pattern in the non-neoplastic areas.
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Macroscopic examination of the right lower lobectomy specimen revealed that the tumor was located at the periphery of the lung It was ill-defined, measuring 11 x 10 x 8 cm in size, with a yellowish-to-whitish cut surface (Fig. 3).
The histological evaluation of the tumor shows papillary structures of epithelial cells without stromal invasion (a). The tumor is composed of squamous cells (b), ciliated columnar cells (c) and a few mucous columnar cells (d) without nuclear atypia. The tumor cells extend along the fibrously thickened alveolar septa forming cystic structures with mucopurulent content (e). The non-neoplastic pulmonary tissue showed usual interstitial pneumonia-pattern fibrosis (g) with fibroblastic foci (inset).
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Microscopically, the tumor was composed of inflamed fibrovascular cores and papillomatous fronds covered by squamous and glandular epithelia (Fig. 4a). It coexisted with the glandular epithelium, which comprised ciliated or non-ciliated pseudostratified columnar cells and a few mucous columnar cells (Fig. 4b-d). The tumor extended along the fibrously thickened alveolar septa or the surface of the reconstructed air spaces (Fig. 4e) with cystic structures often lined by ciliated columnar epithelium with mucopurulent content. The non-neoplastic pulmonary tissue showed subpleural septal fibrosis with many fibroblastic foci, and bronchial or squamous epithelial metaplasia with large air spaces, representing a usual interstitial pneumonia-pattern (Fig. 4f).