Pleomorphic adenoma
Pleomorphic adenoma
Updated: 02/13/2021
© Jun Wang, MD, PhD
General features
- AKA Benign mixed tumor
- Most common tumor of salivary glands
- Most common in parotid gland
- More common in women
- Risk factors for malignant transformation: submandibular location, older age, larger size, radiation exposure
Pathogenesis
- Unclear etiology
- Prior radiation increases risk
- Probably associated with Simian virus (SV40)
Clinical features
- Painless, slow growing tumor
- Usually NOT involving facial nerve
- Rapid growth if malignant transformation (carcinoma ex pleomorphic adenoma)
Pathological features
- Single firm, mobile, well-circumscribed mass
- Triphasic population of benign ductal cells, myoepithelial cells and stromal cells
- Fibrous capsule
- Ductal and myoepithelial components: Commonly glandular,
may be squamous, spindled or oval, myoepithelial cells as the outer layer
- Mesenchymal components: Various, may be myxoid, hyaline, chondroid, adipose or osseous; mucin often present
Genetic abnormality
- PLAG1 rearrangement
Management
- Surgery
- Recurrence uncommon
- May have malignant transformation (carcinoma ex pleomorphic adenoma)
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