PMC6172832_01
Local findings on electron spectroscopy (right channel view). The tumor is indicated by the black arrow
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Fig1
A round tumor with a diameter of approximately 10 mm that involved the posterior end of the nasal septal mucosa at the midline of the epipharynx was discovered in a 58-year-old man while screening for laryngeal cancer (Fig. 1).
Tumor imaging. a Computed tomography image (no enhancement) and (b) magnetic resonance image (T1-weighted image gadolinium positive). White arrows show the tumor
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Fig2
Plain computed tomography (CT) revealed a soft tissue shadow tumor approximately 10 mm in size in the vault of the nasopharynx at the junction of the nasal septum and roof (Fig. 2a). T2-weighted images showed the same intensities as that of the nasal concha, and a regular contrast effect was observed (Fig. 2b). These MRIs suggested a benign tumor.
Hematoxylin-eosin staining of tumor samples. a Tubular formation, (b) papillary structure, and (c) solid growth of spindle cells. All magnifications are x 200
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Fig3
Hematoxylin-eosin staining showed that the tumor had a papillary structure lined by a columnar epithelium with a hyalinized fibrous core, and was additionally composed of sheets of spindle cells (Fig. 3); these two types of structures merged imperceptibly.
Immunohistochemical staining of tumor samples. The left side shows spindle cells while the right side shows columnar cells. The tumor was positive for (a) CK7 and (b) thyroid transcription factor-1, and was negative for (c) PAX8 and (d) p40. All magnifications are x 200
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Fig4
TTF-1 (Fig. 4b), CK19, and vimentin (data not shown); however, they were negative for CK20, p63, smooth muscle actin (SMA), S-100, Epstein-Barr-encoded RNA (EBER), p16, human papillomavirus (HPV), and thyroglobulin (data not shown). The Ki-67 index was approximately 2-3%.