accessory parotid gland

Accessory parotid glands are a normal variant and represent ectopic salivary tissue separate from, but usually in close proximity to, the main parotid glands.

Epidemiology

Accessory parotid glands are commonly picked up incidentally on ultrasound; seen in ~20% of the general population .

Gross anatomy

Located on the lateral aspect of the masseter muscle, anterior to the main parotid gland, usually superior (occasionally anterior) to the main parotid duct (Stensen duct) . They are, on average, within 6 mm of the main parotid gland .

Accessory parotid glands have their own blood supply and secondary duct emptying into the main parotid duct .

Radiographic features

Accessory parotid glands have the same US echotexture, CT density and MRI signal as the main parotid glands.

Differential diagnosis

  • facial process of the parotid gland

Related pathology

Any disorder that affects the main parotid gland may also affect the accessory parotid tissue, but tumors of the accessory parotid glands are rare .

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