Figure 1.

Adenoid cystic carcinoma (ACC) of the left angle of mandible in a 29-year-old female (Case 1). (a,b) A well-defined-margin tumour in the left angle of mandible can be detected on CT and MR images (arrowheads). (c) A plain CT image shows obliteration of fat compared with the right side in the left mandibular foramen (arrow). (d) A contrast-enhanced CT image shows inhomogeneous enhancement in the left mandibular foramen (arrow). (e) A reformatted CT image with bone algorithm shows widening of the left mandibular foramen (arrow). (f) A T₁ weighted MR image shows intermediate signal intensity the same as that of adjacent muscle in the left mandibular foramen (arrow). (g) A T₂ weighted MR image with the fat suppression (FS) technique shows higher signal intensity than that of adjacent muscle in the left mandibular foramen (arrow). (h,i) Contrast-enhanced T₁ weighted MR images with the FS technique show contrast enhancement of the left mandibular foramen (arrows). (j) A histopathologic section shows perineural spread of tumour cells along the inferior alveolar nerve and infiltration of cribriform-type ACC cells for the surrounding tissues (bar 200 μm)