These conditions form part of the spectrum of chronic inflammatory
conditions of unknown origin. All share a common precursor event that is
reduced salivary secretion rate and subsequent stagnation of salivary
flow. These conditions are all more common in the parotid gland because
of thicker saliva, which is more susceptible to bacterial infection than
Chronic recurrent parotitis in infants up to 12 years is more common
in males than females. Chronic sialoadenitis occurs in adults and more
frequently in females than males. Benign lymphoepithelial lesion is more
common in adult females.
Anatomy & Physiology
The parotid gland consists of a superficial (outer) and a deep
(inner) part, which are separated by the tree-like terminal branches of
the facial nerve, responsible for facial movement. Lymph nodes are
present within the gland.
Saliva leaves the gland through Stensen's duct, which pierces the
facial muscles and enters the mouth through the cheek opposite the
second upper molar tooth. Saliva flow is stimulated by chewing and the
presence of food in the mouth, particularly sour substances. The
stimulus is mediated via parasympathetic nerve fibres carried on the
auriculotemporal nerve to the parotid gland.
The submandibular gland consists of superficial and deep parts
separated by the myelohyoid muscle. The duct leaves the deep part of the
gland and enters the floor of the mouth and meets its opposite partner.
The deep part of the gland is intimately related to the hypoglossal
nerve, which moves the tongue, and the lingual nerve, which provides
sensation to the front half of the tongue.
Saliva flow is stimulated via parasympathetic (chorda tympani) nerve fibres carried along the lingual nerve.
The causes are unknown, but both chronic recurrent parotitis and
acute suppurative sialoadenitis can progress onto chronic sialoadenitis.
Chronic recurrent parotitis may also progress into a benign benign
lymphoepithelial lesion or may resolve spontaneously at puberty.
Initially mild recurrent painful swelling of the glands, often
aggravated by eating. It initially lasts for some hours and eventually
becomes a more permanent swelling. In advanced cases, a dry mouth may be
a problem in up to 80% of adult patients, but almost never in children.
Complications of Disorder
Benign lymphoepithelial lesions may rarely go on to develop lymphomas or carcinomas.
The aim of tests should be to rule out treatable predisposing factors
such as stones in the parotid or submandibular ducts, or the narrowing
of the ducts (strictures). This may include:
- Plain X-rays to identify radioopaque stones.
- Sialography, which involves injecting dye into the salivary duct
openings in the mouth to identify non-radioopaque stones and strictures
in the ducts.
- Computed tomographic (CT) scanning with or without sialography.
A biopsy is only required if clinical distinction from tumour is not possible and then requires either:
- Fine needle aspiration cytology (FNAC)
- Open biopsy involving a superficial parotidectomy approach
Fine needle aspiration cytology (FNAC) involves inserting a fine bore
needle into the lump and aspirating some of its contents into a syringe
and the sample is then examined by a cytologist. Although
interpretation of salivary cytology can be very difficult, positive
results can be a helpful guide to treatment planning. Availability of
high quality cytology services is variable. Incisional biopsies of the
parotid are usually avoided because of the high risk of damaging the
facial nerve. Sometimes the only way of obtaining a reliable diagnosis
is to take out the superficial lobe with careful identification of t