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Parotid swelling

Myoepithelial sia|adenitis (MESA)
- Reactive lymphoid cells, plasma cells and histiocytes.
- Clusters of myoepithelial cells sometimes present.

Differential diagnosis:
- Warthin's tumour
- Chronic sialadenitis
- Lymphoepithelial cyst
- Mucoepidermoid carcinoma
- Acinic cell carcinoma
- Non Hodgkin lymphoma
- Perisalivary lymph nodes