In this radiology lecture, we review the ultrasound appearance of pleomorphic adenoma of the parotid gland! Key teaching points include: * Pleomorphic adenoma AKA benign mixed tumor. * Most common salivary gland tumor, most common benign salivary gland tumor, and most common in the parotid gland. * Most common in patients aged 40-50, slightly more common in females. * For salivary gland masses in adults, the larger the gland, the more likely the tumor is benign: Parotid gland: 80%, submandibular gland: 50%, sublingual glands: 20%. * Parotid Gland 80% Rule: 80% of all salivary tumors are in the parotid, 80% of benign parotid gland tumors are pleomorphic adenomas, 80% of pleomorphic adenomas occur in the parotid gland, 80% of pleomorphic adenomas occur in the superficial lobe, and 80% of untreated pleomorphic adenomas stay benign, but 20% can undergo malignant degeneration. * On ultrasound, appears as a well-defined mass with lobulated borders, hypoechoic with posterior acoustic enhancement, and with homogeneity of internal echoes common. * When large, may have cystic degeneration and internal heterogeneity mimicking malignancy. * Vascularity is variable. * Describe lesion location, image-guided biopsy planning, evaluate for cervical lymphadenopathy. * Superficial and deep parotid lobes divided by facial nerve traveling through gland. Nerve not readily seen, but passes just superficial to adjacent retromandibular vein, which can be seen = Use as a landmark. Inferior to the retromandibular vein, may see branches of the external carotid artery. * Treatment is typically excision due to risk of malignant degeneration carcinoma ex pleomorphic adenoma if not completely excised. * DDx includes Warthin tumor: Second most common benign parotid tumor, bilateral in 20%, often exhibit cystic components, most common in elderly. * Malignant parotid tumors are also in the DDx and may appear with ill-defined margins, irregular shape, heterogeneous internal architecture, extraglandular extension, and adjacent lymphadenopathy. * Mucoepidermoid carcinoma: Most common salivary gland malignancy, most common in parotid gland. * Adenoid cystic carcinoma: Second most common parotid malignancy, but most common submandibular and minor salivary gland malignancy. * Higher risk of perineural spread: Patients may present with facial pain and facial nerve paralysis. To learn more about the Samsung RS85 Prestige ultrasound system, please visit: https://www.bostonimaging.com/rs85-prestige-ultrasound-system-4 Click the YouTube Community tab or follow on social media for bonus teaching material posted throughout the week! Spotify: https://bit.ly/spotify-rhq Instagram: https://www.instagram.com/radiologistHQ/ Facebook: https://www.facebook.com/radiologistHeadQuarters/ Twitter: https://twitter.com/radiologistHQ Reddit: https://www.reddit.com/user/radiologistHQ/