Figure 5.

Axial STIR (A), T1-weighted (B) and gadolinium enhanced, fat saturated T1-weighted (C) MRI scans showing a large, well circumscribed, avidly enhancing mass lesion of the deep lobe of the left parotid (arrowheads in A). The images clearly demonstrate infiltration into the parapharyngeal fat (large arrow in B), posterior displacement of the internal carotid artery (large arrowhead in B), anterior displacement of the medial pterygoid muscle (small arrowheads in B) and anterolateral displacement of the retromandibular vein (small arrow in B) suggesting that the facial nerve is laterally displaced by the mass although it cannot be visualised in this case. It was not possible to distinguish with certainty between a pleomorphic adenoma and a malignant tumour on the basis of this scan. Histology showed an acinic cell carcinoma.