Pleomorphic Adenoma / Benign Mixed Tumor
see also: Case Example Deep Lobe Parotid Tumor Parapharyngeal Space
- Benign, slow-growing, heterogenous tumor made up of epithelial, myoepithelial, and stromal components
- Small pleomorphic adenomas can be homogeneously enhancing (<2 cm)
- Large tumors are distinctly lobulated and inhomogeneous
- Deep tumors (10-20%) are pear-shaped and push into the parapharyngeal space medially
- Quite variable in size, can be found as 6-8 cm lesions when located in deep lobe
- Calcification may be present, can help to distinguish from Warthin tumor
- Contrast-enhanced CT or MR are adequate study modalities
- Most common parotid space tumor (80% of all parotid masses)
- Most common in ages >40, 1:2 male to female ratio
- Recurrent pleomorphic adenomas are usually multifocal due to spillage during surgery
- Malignant transformation in 15% if left untreated