PMC4958359_01
Cervical CT image.. Note: Cervical CT showed several inhomogeneous nodules (indicated by the arrows) near the cervical vessels.. Abbreviation: CT, computed tomography.
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Cervical CT revealed several nodulated masses, of which the largest one was nearly 28x24 mm (Figure 1).
Hematoxylin and eosin staining of the thymoma.. Notes: (A) Tumor cells were arranged in a nodular pattern. The infiltrated stroma contained large numbers of lymphocytes with formation of lymphoid follicles. Scale bar is 800 mum. (Original magnification x100.) (B) Epithelial tumor cells were oval shaped with occasionally atypia or mitotic activity. Scale bar is 300 mum. (Original magnification x200.) (C) Eosinophilic granulocytes infiltrated the tumor nodules and the surrounding stroma. Scale bar is 300 mum. (Original magnification x200.) (D) High magnification showed the infiltrated eosinophilic granulocytes and the proliferating LCs. Nuclear grooves (indicated by the arrow) could be observed in some LCs. Scale bar is 100 mum. (Original magnification x100.). Abbreviation: LCs, Langerhans cells.
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Histologically, it was composed of multiple tumor nodules separated by hyperplastic lymphoid tissues with prominent germinal centers (Figure 2A). The tumor cells within the nodules were mostly oval-to-spindle shaped, with nuclei containing dispersed chromatin and inconspicuous nucleoli (Figure 2B). Eosinophilic granulocytes were found to infiltrate the tumor nodules and the surrounding lymphoid stroma (Figure 2C). Langerhans cells (LCs) were mainly scattered within the tumor nodules, and nuclear grooves could be observed (Figure 2D).
Immunohistochemical staining of the thymoma.. Notes: Proliferation of epithelial tumor cells were stained by CK (pan) (A), CK5/6 (B), and P63 (C). Proliferated LCs were positive for CD1a (D) and S100 (E). Mature B lymphocytes were positive for Pax-5 (F). Scale bar is 800 mum. (Original magnification x100.). Abbreviation: LCs, Langerhans cells.
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The tumor cells in the nodules showed strong positivity for pan-CK (Figure 3A), CK5/6 (Figure 3B), and P63 (Figure 3C), while they were negative for CD20, CK20, and CK7. CD1a (Figure 3D) and S100 (Figure 3E) staining showed that the proliferating LCs were distributed in the tumor nodules. The hyperplastic stroma was primarily formed by large numbers of mature B lymphocytes expressing Pax-5 (Figure 3F) and CD20 as well as mature T lymphocytes reactive for CD3 and CD5.