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FIG 3. Case 3.
A–C, Axial contrast-enhanced CT scans show an enhancing soft-tissue mass (arrows, A) lying against the enlarged and enhancing right submandibular salivary gland (star). At a higher level (B), the mass (arrows) cannot be distinguished from this gland. In C, the soft-tissue mass extends into the medial pterygoid muscle (arrows), abutting the right oropharyngeal wall; there is infiltration of the fat in the mandibular foramen (arrowhead) and associated sclerosis of the mandibular ramus, which appears slightly deformed.
D, Axial T2-weighted MR image shows a poorly defined soft-tissue structure, more or less isointense with fat, in the right masticator space.
E, Unenhanced T1-weighted image shows that the mass is largely isointense with muscle, with some small low-intensity areas (arrows); some signal loss is evident in the right mandibular ramus.
F, After injection of contrast material, there is clear enhancement within the mass, except for the previously indicated low-signal areas, which possibly correspond to areas of fibrosis.
G, Coronal T1-weighted image shows the mass infiltrating the medial pterygoid muscle up to its attachment at the skull base (arrows); the submandibular salivary gland is displaced inferiorly (star).
H, Low-power histologic section shows spindle cells embedded in a collagenous background and intermingled with mononuclear inflammatory cells (H and E, original magnification x125).
I, At high power, the admixture of the inflammatory cells and the plump (myo)fibroblastlike cells is seen to a better extent (H and E, original magnification x325).
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