PMC4564912_01
Loosely dispersed malignant cells with round to oval nuclei, irregular nuclear borders, stippled chromatin pattern, inconspicuous nucleoli, and scant cytoplasm (Papanicolaou, x600)
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F1
The thin prep smears stained with Papanicolaou showed malignant cells arranged singly [Figure 1], in clusters [Figure 2] and occasional single-file pattern [Figure 3]. The individual cells showed round to oval nuclei, irregular nuclear borders, stippled chromatin pattern, inconspicuous nucleoli, and scant cytoplasm [Figure 1].
Malignant cells arranged in clusters with occasional mitotic figures (Papanicolaou, x600)
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F2
The thin prep smears stained with Papanicolaou showed malignant cells arranged singly [Figure 1], in clusters [Figure 2] and occasional single-file pattern [Figure 3]. Mitotic figures were identified [Figure 2].
Malignant cells arranged in single-file pattern with focal nuclear molding (Papanicolaou stain, x600)
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F3
The thin prep smears stained with Papanicolaou showed malignant cells arranged singly [Figure 1], in clusters [Figure 2] and occasional single-file pattern [Figure 3].
Cell block showing loosely dispersed malignant cells with high nucleus to cytoplasmic ratio, fine to clumped chromatin pattern, occasional small inconspicuous nucleoli, irregular nuclear borders, and scant eosinophilic cytoplasm (H and E, x400)
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F4
The cell block preparation stained with hematoxylin and eosin showed loosely dispersed malignant cells with high nucleus to cytoplasmic ratio, fine to clumped chromatin pattern, occasional small inconspicuous nucleoli, irregular nuclear borders, and scant eosinophilic cytoplasm [Figure 4].
Tumor cells with "dot-like" rim pattern of staining with CK20 (x400)
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F5
Immunohistochemical stains showed the tumor cells were immunoreactive for AE1/AE3, CK20 [Figure 5], chromogranin, synaptophysin, and Merkel cell polyomavirus (MCPyV) monoclonal antibody (CM2B4) [Figure 6].
Few tumor cells showing nuclear staining with Merkel cell polyomavirus monoclonal antibody (CM2B4) (x400)
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F6
Immunohistochemical stains showed the tumor cells were immunoreactive for AE1/AE3, CK20 [Figure 5], chromogranin, synaptophysin, and Merkel cell polyomavirus (MCPyV) monoclonal antibody (CM2B4) [Figure 6].