Salivary gland diseases include disorders of the major sali- vary glands (parotid, submandibular or sublingual) or minor salivary glands (600–1000 in number) dispersed throughout the upper aerodigestive submucosa (i.e. oral cavity, pharynx, larynx, parapharyngeal space, paranasal sinuses).
Epidemiology
Major salivary gland diseases are much more common than mi- nor salivary gland disorders. The parotid glands (Figure 5.12) are affected more often than submandibular glands, and sublingual glands are the least affected.
Causes
A summary of the varied causes of salivary gland diseases is presented in Table 5.5.
Nearly 100% of sublingual, 80% of minor salivary gland, 50% of submandibular and 20% of parotid gland neoplasms are malignant.
Figure 5.12 Malignant tumour of the right parotid gland with local spread to the overlying skin.
Infective Viral: mumps, HIV, cytomegalovirus, Epstein-Barr virus,
coxsackievirus, measles, echovirus
Acute bacterial: Staphylococcus aureus, Haemophilus influenzae, Streptococcus viridians
Chronic bacterial: acute infection as above, Mycobacterium tuberculosis, actinomycosis, Bartonella henselae, syphilis
Inflammatory Sjögren’s syndrome (salivary gland involvement is seen in 40% of cases, 33–44% of these develop lymphoma in later life)
Sarcoidosis (parotid enlargement with facial nerve palsy and uveitis is Heerfordt’s syndrome)
Wegener’s granulomatosis
Juvenile recurrent parotitis (symptoms stop at puberty)
Neoplastic Benign: pleomorphic adenoma (65% of all salivary
tumours), papillary cystadenoma lymphomatosum (Warthin’s tumour in 6–10% of all parotid tumours, with 10% bilateral)
Malignant (Figure 5.12): mucoepidermoid carcinoma
(commonest, 6–9% of all salivary gland cancers, parotid > submandibular), adenoid cystic carcinoma (second commonest, 6% of all salivary gland cancers, submandibular > parotid), carcinoma ex-pleomorphic adenoma (2–5% of all salivary gland tumours), acinic cell carcinoma, adenocarcinoma, metastasis
Degenerative Stone (sialolith): submandibular gland/duct (80% of
cases, 90% are radio-opaque), parotid (19% of cases, 90% are radiol ucent), sublingual and minor salivary glands (1% of cases)
Cysts: mucous extravasation cysts, mucous retention cysts
and ranula (large mucous cyst of floor of mouth region)
Others: amyloidosis, cirrhosis, Cushing’s disease,
diabetes, gout, bulimia, alcoholism, hypothyroidism and drugs, e.g. thiouracil
Table 5.5 Causes of salivary gland disease
Clinical features
A detailed history with a thorough review of systemic symp- toms and drug history is essential. The commonest presenting symptom is swelling of the involved salivary glands. Other symptoms include:
Head and neck Salivary gland diseases 181 • mouth dryness • halitosis • pain or increased swelling with eating • decreased mouth opening • cranial nerve palsies (facial, lingual, hypoglossal) • dryness of the eyes • systemic symptoms in cases of infective and inflammatory pathology.
A thorough examination should include bimanual palpation of the salivary glands and their ducts, neck nodes, cranial nerve assessment, and nasendoscopy of the pharynx. Parotid swellings appear adjacent to the ear near the angle of the jaw; submandibular swellings appear below the mandible, and sublingual swellings in the floor of the mouth.
Acute infections usually result from ascending spread from the oral cavity or haematogenous spread. Dehydration or ob- structed glands, malnutrition, immunosuppression and poor oral hygiene are predisposing factors. Painful swellings are usually infective or inflammatory in origin, although adenoid
cystic carcinomas can cause pain. Painless swellings indicate a neoplastic, degenerative or chronic infective process.
Investigation
Haematological Haematological tests include FBC (showing raised WBC in infection), CRP (raised in presence of inflamma- tion), ACE (raised in sar coidosis), ANCA (positive c-ANCA, in Wegener’s granulomatosis), serological tests for viruses includ- ing mumps and HIV, specific autoantibodies (Rho and La), and antinuclear antibodies and rheumatoid factor (suggesting Sjögren’s syndrome).
Microbiology Pus is taken for microscopy, culture and guid- ance on antibiotic sensitivities.
Plain radiographs These are useful for calculus disease, espe- cially of the submandibular glands (Figure 5.13).
Ultrasonography This is usually the first-line investigation, with FNA for investigation of a parotid/submandibular gland swelling. CT/MRI Cross-sectional imaging is necessary for neoplastic dis- ease to delineate the extent and spread of the tumour and plan resection.
Interventional sialography This can be used for direct evaluation of the ducts and also has the advantage of pos- sible therapeutic intervention (balloon angiography, basket retrieval of calculi).
Management
The specific management depends on the cause. Only a brief overview is presented here.
General measures include attention to oral hygiene (aided by an antiseptic mouthwash) and hydration to maintain good salivary flow.
Open biopsy is almost totally contraindicated in salivary gland swellings, the exception being neoplasms of the minor glands, as tumours spilt by biopsy will seed the area and result in the development of multiple recurrences within the biopsy scar. FNA biopsy is the method of choice.
Head and neck Pharyngeal pouch 183 • Acute viral infections require supportive treatment, although
HIV requires specialist involvement
• Acute bacterial infection requires an broad-spectrum antibiotic covering aerobic and anaerobic organisms (e.g. co-amoxiclav); consider the intravenous route if there is systemic disturbance or difficulty taking oral fluids • Abscesses may require incision and drainage, with careful
regard to the facial nerve. Chronic infection such as TB should be referred to a chest physician for anti-tuberculous medication
• Inflammatory causes (e.g. Sjögren’s, sarcoidosis, Wegener’s) should be managed with the help of a rheumatologist as steroids and immune-modulating drugs will be required. Rarely parotidectomy or submandibular gland excision is needed for intractable swelling or pain associated with inflammatory diseases
• Salivary gland or duct stones may be retrieved with interventional sialog- raphy or require either local excision or gland excision together with the stone • Patients with neoplastic le-
sions should be discussed in the multidisciplinary team meeting to agree an appro- priate management plan.
Prognosis
Benign salivary gland disease generally has a favourable outcome, although facial nerve compromise after parotidec- tomy can have considerable social and emotional impact. For malignant disease, the stage of disease at presentation (TNM classification) correlates the best with ultimate outcome.
5.7 Pharyngeal pouch
Pharyngeal pouches arise as a result of herniation of the pos- terior pharyngeal mucosa through a relatively unsupported
Frey’s syndrome or gustatory sweating can occur after parotidectomy. There is redness and sweating on the ipsilateral face/neck when the patient smells, eats or even talks about food. This response is caused by regenerating parasympathetic fibres severed for salivary secretion inappropriately attaching to the sympathetic fibres in the skin
part of the upper oesophageal sphincter. This weak part of the posterior pharyngeal wall, termed Killian’s dehiscence, lies between the cricopharyngeus and thyropharyngeus.
Epidemiology
The outpouching of the pharyngeal mucosa is also referred to as posterior pharyngeal pulsion (Zenker’s) diverticulum. The incidence is approximately 1 in 200 000 population per year. It occurs more commonly in elderly men than in women.
Causes and pathogenesis
The aetiology is unknown but the pathogenesis is probably multifactorial. Several theories, including weakness of the Killian’s dehiscence, incoordination of the first (pharyngeal) phase of swallowing and an increase in intrapharyngeal pres- sure and cricopharyngeal muscle spasm, could be contribu- tory factors. Hiatus hernia and gastro-oesophageal reflux are sometimes present.
As it enlarges the pouch becomes symptomatic; food can enter the pouch preferentially and in the later stages the pouch extends into the posterior mediastinum, exerting pressure on the oesophagus and resulting in dysphagia.
Clinical features
Small pouches may remain asymptomatic. The common presenting symptoms include a sensation of a lump in the throat, gradually worsening dysphagia and regurgitation of undigested food with halitosis. Weight loss and recurrent chest infection due to aspiration may prompt urgent referral. The swelling in the neck, usually on the left side, may gurgle and empty with external pressure.
Diseases restricting neck movements and limited jaw opening reduce surgical access and affect management. Elderly patients with recurrent chest infections and aspiration have a poor pulmonary reserve, adding to general anaesthetic risk.
Head and neck Pharyngeal pouch 185
Investigation
A plain radiograph of the neck and cervical spine may show an air-filled space in the pouch and the state of the cervical verte- brae. The definitive investigation is a barium swallow (Figure 5.14) that demonstrates the pouch. A rigid oesophagoscopy is carried out prior to surgical treatment to exclude carcinoma in the wall of the pouch.
Management
Asymptomatic patients may be treated with a conservative ‘wait and watch’ policy, as the pouch may remain static in size for quite some time. In symptomatic patients endoscopic stapling is the treatment of choice. However, difficult anatomy with limited neck extension, restricted jaw opening and protrud- ing upper teeth may preclude endoscopic approaches. Small pouches are sometimes not amenable to endoscopic stapling if the amount of tissue separating the pouch from the pharynx (the ‘bar’) is too small for the staple gun to be engaged. Larger
a b
Figure 5.14 Barium swallow from the same sequence outlining a pharyngeal pouch. In (a) the barium has half-filled the pouch and in (b) the pouch is fully filled.
pouches are clearly visualised (Figure 5.15) and a thorough inspection to exclude carcinoma is carried out before stapling and dividing the bar between the pouch and the oesophagus (Figure 5.16).
The main disadvantage of endoscopic surgery is that the pouch is not excised but opened into the oesophagus to allow the passage of food. The advantages of endoscopic stapling, however, far outweigh the risks:
• Reduced surgical time and hospital stay • Avoids suture lines in the neck and oesophagus
• Significantly reduces the risk compared to open procedures. In patients in whom endoscopic techniques have failed or have not been possible because of anatomical factors, open procedures are used. This could be a diverticulotomy, where the pouch is excised, combined with myotomy of the crico- pharyngeal muscles. Some surgeons do not excise the sac but
Figure 5.15 Endoscopic view of the bar between the pharyngeal pouch (seen posteriorly) and the oesophagus (anteriorly).
Figure 5.16 Endoscopic view following stapling of the bar: the pouch wall is incorporated as part of the wider oesophageal wall.
Head and neck Benign neck lumps 187 invert and oversew the pouch to avoid the risk of opening and suturing the oesophagus. Nasogastric feeding is required for 5–7 days postoperatively.
Prognosis
The majority of patients improve symptomatically following endoscopic stapling; a small proportion (<8–10%) who remain symptomatic may require a second stapling procedure. Quality of life improves following surgical treatment, with the ability to eat all types of food and the prevention of aspiration and recurrent chest infections.