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A further PASD stain was performed, in which the diastase enzyme would ingest glycogen. This test indicated the presence of glycogen.
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The cells demonstrated a typical small round blue cell tumour phenotype (See Figure 5).
A Reticalin stain was performed, which showed a distinct pattern of cellularity typical in embryonal rhabdomyosarcoma.
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Figure 8). Finally, a Reticalin stain was performed, which showed a distinct pattern of cellularity typical in embryonal rhabdomyosarcoma (See Figure 6).
The MRI shows a large, well-defined lobulated solid mass lesion located in the right masticator space deep to the angle of the right mandible.
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A PAS stain was performed, which was pink to indicate the presence of glycogen and/or mucin (See Figure 7).
The MRI shows that the mass is approximately 5.2 x 4.3 cm (AP x transverse), centered in the right half of the face/neck.
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Figure 8). Finally, a Reticalin stain was performed, which showed a distinct pattern of cellularity typical in embryonal rhabdomyosarcoma (See Figure 6).
The MRI shows smaller, cystic regions scattered in the mass lesion. It extends medially to affect the right pharyngeal mucosal space, with notable effacement of the oropharynx.
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Desmin stain was positive, indicating the presence of muscle cells (See Figure 9). Desmin is an intermediate filament protein present in smooth muscle cells, striated muscle cells and myocardium.
The MRI shows that the adjacent right mandibular body and angle show good cortical outline. There is no definite cortical destruction indicated.
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MyoD1 stain, an immunohistochemical stain, was also performed, and found to be positive (See Figure 10). MyoD1 is a primitive transcription factor that regulates Desmin production, and confirmed the muscle origin of the tumour and its primitive characteristics.