## Pleomorphic Adenoma: Key Characteristics ### Epidemiology & Location **Key Point:** Pleomorphic adenoma is the most common benign salivary gland tumor, accounting for 60–70% of all parotid tumors and 40–50% of submandibular tumors. **Clinical Pearl:** The superficial lobe of the parotid gland is the site of origin in 80% of cases, making it the most common location for this tumor. ### Malignant Potential **High-Yield:** Pleomorphic adenoma has a risk of malignant transformation (carcinoma ex pleomorphic adenoma) of 5–15% if left untreated for >20 years. This risk increases with tumor duration and age at presentation. ### Diagnostic Modalities | Modality | Sensitivity | Specificity | Role | | --- | --- | --- | --- | | FNAC | 60–80% | 95–98% | Screening tool, NOT gold standard | | Core needle biopsy | 85–95% | 95–99% | Better accuracy than FNAC | | MRI | 90–95% | 85–90% | Best for imaging, defines extent | | Excision biopsy | 100% | 100% | Gold standard (definitive diagnosis) | **Warning:** FNAC has a sensitivity of only 60–80%, not >95%. It is a useful screening tool but NOT the gold standard. Core needle biopsy or excision biopsy provides definitive diagnosis. The statement claiming FNAC is the gold standard with >95% sensitivity is **FALSE**. ### Treatment **Key Point:** Superficial parotidectomy with facial nerve preservation is the standard treatment. Wide local excision is adequate for small tumors in the superficial lobe. [cite:Robbins 10e Ch 16] [cite:Harrison 21e Ch 71]
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