Most pleomorphic adenomas present as rounded, well-demarcated masses rarely exceeding 6 cm.
They are well defined and surrounded by capsule most of the time but in some areas like the hard palate the capsule is not completely formed and results in protrusions into the surrounding gland.
The significance of this is that recurrence will occur if only enucleation is done so a wide local resection has to be done to prevent recurrence.
On cut section, they will have a gray white to myxoid to blue cut surface. This bluish hue is representative of the chondroid tissue (cartilage like)
There is both an epithelial and mesenchymal component because it’s a mixed tumour. The epithelial component consist of epithelial cells, myoepithelial cells which line well-formed ducts. They are presentin loose myxoid tissue containing islands of cartilage and sometimes even bone.
A carcinoma arising in a pleomorphic adenoma is referred to as a carcinoma ex pleomorphic adenoma or a malignant mixed tumor.
The incidence of malignant transformation increases with the duration of the tumor.
Once they turn malignant they are highly aggressive with high mortality rates