case_images: PMC8552398_01
case_images: Chest CT shows a well-defined, part-solid nodule in the superior lingular segment of the left upper lobe, with slightly lobulated contour, interlobar pleural retraction (arrow), and air bronchogram (arrowhead).
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case_images: A chest computed tomography (CT) showed a well-defined, part-solid nodule (PSN), measuring 20 x 19 mm in the superior lingular segment of the left upper lobe, with slightly lobulated contour and interlobar pleural retraction (Figure 1).
case_images: (a) Intraoperative cytology of nodular lesion shows clusters of tumor cells of high N/C ratio, granular chromatin, and scant basophilic cytoplasm (May Grunwald Giemsa [MGG] stain, x400). (b) In the background are seen many little lymphocytes, histiocytes, peripheral blood, and some benign bronchial cells (arrow) (MGG, x100).
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case_images: The intraoperative cytology examination showed clusters of uniformly atypical cells in monolayer sheets and single cells with high nucleus-cytoplasm (N/C) ratio, scant basophilic cytoplasm, anisonucleosis with one or more usually small and occasionally prominent nucleoli, and granular chromatin (Figure 2(a)). In the background, there were lots of little lymphocytes, some plasma cells, histiocytes, and peripheral blood (Figure 2(b)).
case_images: (a, b) Pathohistological staining of the well-circumscribed mass of nodular lymphoid hyperplasia in the lung (c) with reactive well-developed secondary lymphoid follicles. (d) On the higher magnification, germinal center cells, interfollicular lymphocytes, plasma cells, histiocytes, neutrophils, and eosinophils are seen.
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case_images: Pathohistological findings in the resected lung showed a well-demarcated mass (Figure 3(a) and (b)) composed of reactive germinal centers, well-preserved mantle zones, and sheets of interfollicular mature plasma cells, lymphocytes, histiocytes, and neutrophils (Figure 3(c) and (d)).
case_images: (a) Parenchymal pulmonary lesion close to respiratory bronchioles characterized by lymphoid hyperplasia and fibrosis around the alveoli. (b) The alveoli are lined by atypical cells. (c and d) On higher magnification, the pleomorphic cells focally densely packed showing cell-cell contact can be seen.
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case_images: Granuloma, necrosis, amyloid depositions, and Dutcher's bodies were not observed, but interfollicular fibrosis and fibrosis around the alveoli close to respiratory bronchioles could be found (Figure 4(a)). The alveoli were lined by atypical cells (Figure 4(b)). On higher magnification, the pleomorphic cells were focally densely packed showing cell-cell contact (Figure 4(c) and (d)).
case_images: (a) Immunohistochemical staining with CD20 shows tightly packed B cells predominantly within reactive follicles and (b) CD3+ T cells outlining the follicles and throughout the interfollicular space. (c) Plasma cells stained with anti-CD38 are numerous in the interfollicular space, (d) while IgG4+-plasma cells are very rare.
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case_images: T lymphocytes (Figure 5(a) and (b)). Bcl-2 was absent in the reactive germinal centers, although BCL-2 was noted in the mantle cells and T lymphocytes within and between germinal centers. The heterogeneous reaction was observed in the number of perifollicular plasma cells with CD38 (Figure 5(c)), lambda, and kappa antigens. Staining with IgG4 was seen at low levels in plasma cells (Figure 5(d)).