Parotitis is usually bilateral. The glands will be enlarged and heterogeneous with increased vascularity as shown below.
Parotitis extending into the accessory Parotid gland.
Marked hyperaemia confirms that this is an active process.
Is an autoimmune disorder affecting the moisture producing exocrine glands (tears and saliva). It is suggested to be the 2nd most prevalent rheumatic disorder (2nd to Rheumatoid arthritis). Symptoms can often be only nuisance value, so many cases are thus unreported.
Symptoms may include dryness of eyes/mouth (Sicca syndrome)
MALT lymphoma may occasionally develop in the parotid glands of Sjogren’s patients
The diffuse lymphadenititic nodules seen throughout the parotid in Sjogrens syndrome.
A benign and not uncommon finding.
Aspiration under ultrasound guidance if symptomatic.
Simple cysts may occur in either the Parotid or Submandibular glands.
Cysts may become complex. Mural thickenings or nodules warrant further investigation or follow-up depending on clinical presentation.
Any internal vascularity of the mural change should be treated with suspicion.
Parotid calculus and sialectasis
Sialectasis (or sialectasia) is the dilatation of the salivary ducts within the salivary gland.
This may appear as ‘cystic dilatations’ of the ducts (ectatic).
Ultrasound of ectatic parotid sialectasis (duct dilatation)
The dilated parotid duct exiting the parotid gland. Sialectasis may only be transient and present after eating or stimulating the parotid.
By asking the patient to hold water in their mouth and ‘puff’ it into their cheek, the distal duct can be examined. (see image below)
The calculus is easily seen in the Stensen’s duct as it exits the main body of the parotid gland heading medially.
Parotid duct calculi are less common than submandibular duct calculi..
Ultrasound of the distal parotid duct (green) and ampulla. Water (blue) has been used as a contrast and to expel oral air, by asking the patient to squeeze a mouthful into their cheek
Ultrasound is a very useful tool to investigate parotid pathology. In the case of neoplasms, the role of ultrasound is to accurately differentiate malignant from benign is widely disputed.
In any case of a parotid lesion, FNA or biopsy should be considered, as features of both often overlap.
Parotid adenoma / adenocarcinoma
Adenomas are more common than adenocarcinomas.
Incidence of adenocarcinoma is approximately 1:100,000 with a 70% 5yr survival. (ref: cancer.net)
NB: ultrasound cannot distinguish between the two.
There is an increased risk of adenocarcinoma in patients who have undergone head/neck radiation treatments.
Adenomas of the salivary glands are usually hypoechoic, well-circumscribed and have posterior enhancement. An adenocarcinoma cannot be excluded on ultrasound criteria alone.
Internal vascularity confirms a solid mass versus a complex cystic lesion.
NB: Absence of seeing flow on colour doppler does not exclude a solid tumor. It simply means that now flow was detected/discernable on colour doppler.
B-mode and colour Doppler image of a pleomorphic adenoma.
An ovoid, well-circumscribed hypoechoic and vascular mass containing cystic spaces.
Images courtesy of Callum Linehan.
B-mode and colour Doppler image of a pleomorphic adenoma. A case of a solid inhomogenous lobulated hypoechoic lesion containing vascularity.
Images courtesy of Callum Linehan.
Ultrasound image of a pleomorphic adenoma. A large heterogenous vascular mass, note the margins are still well circumscribed.
The patient presented for a scan for a lump in the left parotid region. This was diagnosed as an inflammatory lymph node. Comparison with the rt side was then done (mouseover).
The appearance was initially confusing as the parotid gland could not be found. There was hypoechoic tissue that looked like fat in the space the parotid should be occupying. The diagnosis of parotid atrophy was confirmed by comparing it to a CT Brain that had been performed 12 months earlier.
The same patient had a brain CT 12months earlier.
A comparison was made after the ultrasound and it helped confirm the atrophy of the Parotid gland.
The abscent/atrophied right parotid is notable in both the coronal and axial scan planes.