PMC4189945_01
Axial view of CT showing dimensions of the tumor.
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Conventional computed tomography (CT) (Figure 1) and CT angiography (Figure 2) demonstrated a left parapharyngeal mass 3 x 4 x 9 cm, displacing the left internal carotid artery, external carotid artery, and internal jugular vein, with no evidence of vascular infiltration.
Coronal view of CT angiography showing left parapharyngeal and pharyngeal mainly hypodense, peripherally hyperdense well-defined lesion (7 x 4 x 3 cm) indenting the left pharyngeal wall but not infiltrating it.
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fig2
Conventional computed tomography (CT) (Figure 1) and CT angiography (Figure 2) demonstrated a left parapharyngeal mass 3 x 4 x 9 cm, displacing the left internal carotid artery, external carotid artery, and internal jugular vein, with no evidence of vascular infiltration.
Cross-sectional image of the excised tumor.
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The cut surface showed microcysts, hemorrhage, and necrosis with brownish areas (Figure 3).
Malignant triton tumor showing the following: (a) well delineated spindle cells with scattered rhabdomyoblasts (H&E x100), ((b) and (c)) higher magnification (x200 and x400), and (d) cross striations of rhabdomyoblast cells stained with phosphotungstic acid hematoxylin (x400).
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Large pleomorphic cells with abundant eosinophilic cytoplasm and rounded eccentric nuclei with large nucleoli were present (Figures 4(a), 4(b), and 4(c)). These cells were identified on hematoxylin and eosin and phosphotungstic acid hematoxylin stains (Figure 4(d)).
Immunohistochemical staining of malignant triton tumor showing the following: (a) diffuse positivity for S-100 protein (x200), (b) desmin positivity in the rhabdomyoblast cells (x200), and (c) myoglobin positivity in the rhabdomyoblast cells (x400).
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Immunohistochemical staining (IHS) of the tumor revealed diffuse, intense positivity of the wavy spindle cells for S-100 protein, confirming its neurogenic origin (Figure 5(a)). Myogenic differentiation of the large pleomorphic cells was confirmed by the strong positivity for desmin (Figure 5(b)) and moderate positivity for myoglobin (Figure 5(c)).