Head and neck
Tumours of the nasal cavity, sinuses, and nasopharynx
Nasal cavity and paranasal sinuses
Epidemiology
• 0.2–0.8% of all cancers; 3% of head and neck malignancies.
• 60% maxillary sinus, 25% nasal cavity, 14% ethmoid, 1% sphenoid and frontal.
• More frequent in men and in the fifth decade.
• Presentation is late with T3/4 disease.
• Increased incidence in the Far East.
Risk factors
• Cigarette smoke and alcohol (especially in combination).
• Occupational agents such as wood dust, nickel, and chromium, which seem to exert a synergistic effect.
• Organic chemicals (e.g. benzene), ionizing radiation, oncocytic papilloma, and possibly HPV may play a role.
Pathology
• Benign tumours include osteoma and fibroma.
• Malignant tumours can be subdivided as follows:
• Epithelial—SCC (75–90% generally well or moderately differentiated), adenocarcinoma (accounts for 45% of carcinoma with occupational causes), malignant melanoma, undifferentiated carcinoma, small cell carcinoma, adenoid cystic carcinoma.
• Osseous–osteogenic sarcoma, Ewing's sarcoma.
• Connective tissue–chondrosarcoma, fibrosarcoma.
Diagnosis
History and examination, scrapings, incisional biopsy or excisional biopsy if small, and FNA of any palpable node will all aid diagnosis.
Investigations
Baseline blood investigations to look for malnutrition, anaemia, and liver metastases; FBC, U&E, LFT, thyroid function tests, clotting, cross-match (pre-operative 4–6 U). CXR, OPG (if tumour may be invading mandible), CT/MRI (to detect the extent and infiltration of the tumour and any nodes >1.5 cm or spherical with central necrosis), and chest CT scan for staging purposes. Comprehensive examination under anaesthetic should include palpation and panendoscopy.
Management
This requires a multidisciplinary team including an oncological surgeon, reconstructive surgeon, specialist nurse, speech therapist, dietician, oral hygienist, dentist, prosthodontist, psychologist, social worker, administrative and audit support, and an ex-patient.
Supportive management
Assessment by the above team and ensure suitable pre- and post-operative support as appropriate. Pre-operative feeding via an NG tube, PEG tube, or jejunostomy. Blood transfusion or tracheostomy may be required. Dental evaluation prior to radiotherapy. Helping the patient to stop smoking is important, as radiotherapy is less effective in patients who continue to smoke.
Maxillary carcinoma
Clinical features
• Nasal symptoms such as epistaxis, rhinorrhea, obstruction, swelling, and pain.
• Oral symptoms including loosening of teeth, referred molar pain, ulceration, or fistula of the hard palate.
• Ocular problems such as proptosis, swelling of the eyelids, and excessive tearing.
• Facial signs of swelling and asymmetric cheeks.
• Neurological evidence of involvement of the infra-orbital nerve.
TNM classification
• TX, T0, Tis: as for oral cavity tumours.
• T1: tumour in maxillary sinus mucosa.
• T2: tumour into bone but not posterior wall.
• T3: tumour invading any of posterior wall, subcutaneous tissues, orbital floor or medial wall, infra-temporal fossa, pterygoid plates, ethmoid sinus.
• T4: tumour into orbital contents beyond floor or medial wall, dura, brain, or nasopharynx.
• N and M as oral cavity.
Staging
• Stage 1: T1, N0, M0.
• Stage 2: T2, N0, M0.
• Stage 3: T3, N0, M0 or T1–3, N1, M0.
• Stage 4: T4, N0–1, M0 or T1–4, N2–3, M0–1, any T, any N, M1.
Treatment
Multidisciplinary team approach
Surgery and radiotherapy for all stages if the disease is resectable, including skull base resection for more advanced disease. Orbital exenteration should be performed if there is evidence of ocular involvement. If the tumour is in the orbital floor alone the eye can be saved, but if the orbital floor is resected and post-operative radiotherapy is planned many experts recommend eye removal anyway because of post-radiotherapy morbidity.
Reconstruction
• If the skin and orbit are preserved no reconstruction is needed.
• If the hard palate alone is involved a palatal prosthesis will suffice.
• With orbit and skin loss a fasciocutaneous flap is used (radial forearm flap).
• With loss of orbit, skin, and hard palate, a myocutaneous flap should be placed to fill the space (VRAM) using a double-skin paddle to reconstruct skin and hard palate mucosa.
Prognosis
• Local recurrence in 45%, mostly in the first year.
• Nodal disease in 22% and distant metastases in 18%.
• Five year survival is ∼42%.
• >75% chance of mortality if patient presents with orbital, palatal, or infra-orbital nerve involvement.
• Tumours anterior and inferior to Ohngren's line (medial canthus to angle of the mandible) have a better prognosis.
Nasal cavity tumours
Nasopharyngeal carcinoma
Anatomy
The nasopharynx continues from the nasal cavity anteriorly, including the post-nasal space. It ends inferiorly at an imaginary line between the upper surface of the soft palate and the posterior pharyngeal wall. Inferior to this is the oropharynx.
Epidemiology
0.25% of all carcinomas in Caucasians. Mainly occurs in the fifth decade. Common in southern China and in sub-Saharan and North Africa.
Risk factors
• Race.
• EBV.
• Genetic HLA link.
• Nitrosamines and nasal balms.
• Alcohol and smoking do not appear to be linked.
TNM classification
• Tx, Tis, T0, as for oral cavity tumours.
• T1: tumour confined to the nasopharynx.
• T2: tumour extends to the soft tissues in oropharynx, nasal cavity, or parapharynx.
• T3: tumour into bone or paranasal sinuses.
• T4: tumour with intracranial extension or to hypopharynx orbit or cranial nerves.
• NX, N0: as oral cavity.
• N1: unilateral node <6 cm above supraclavicular fossa.
• N2: bilateral nodes <6 cm above supraclavicular fossa.
• N3: lymph node metastases >6 cm or in supraclavicular fossa.
• MX, M0, M1: as above.
Staging
• Stage 1: T1, N0, M0.
• Stage 2: T1, N1, M0 or T2, N0–1, M0.
• Stage 3: T1-2, N2, M0 or T3, N0–2, M0.
• Stage 4: T4, N0-2, M0, or any T, N3, M0, or any T, any N, M1.
Clinical features
Nasal obstruction, epistaxis, otitis media, and asymptomatic upper jugular neck mass. The most common site is the lateral wall near the Eustachian tube. At presentation, lymph nodes are involved in 70% of cases (bilateral in 35%), the skull base is involved in 30%, and the cranial nerves may also be involved. Distant metastases are rare (<5%).
Treatment
• Stage 1: radiotherapy to primary and neck.
• Stages 2–4: either radiotherapy alone or chemo-radiotherapy.
• Surgical management is reserved for persistent or recurrent lymphadenopathy of the N2 neck. In selected cases it may be used for recurrent disease.
Tumours of the oral cavity, oropharynx, and hypopharynx
Anatomy
The oral cavity is defined as the area from the start of the lip vermilion to the junction of the hard and soft palates above to the line of the circumvallate papillae below. The oropharynx extends from there back to the tip of the epiglottis, which is at the level of the hyoid. The hypopharynx extends from the lower point of the oropharynx above to the plane of the inferior border of the cricoid cartilage below.
Epidemiology
These comprise 3% of all tumours in men and 2% in women. In India they comprise 40% of all cancers. Most common in sixth and seventh decades.
Pathology
Over 90% are squamous cell carcinomas. Other tumours include accessory salivary gland tumours, lymphoma, bone tumours, secondary deposits, spindle cell carcinoma, verrucous carcinoma, malignant melanoma, and sarcoma.
Risk factors
• The long-term use of tobacco and alcohol is related to 75% of cases.
• Spices, betel quid chewing, and smoking of bidis in India.
• Other risk factors are malnutrition, chronic irritation from dentures or poor dentition, chronic infection, marijuana, occupational agents such as nickel and formaldehyde, immunosuppression, previous tumour, and premalignant lesions.
• Viral aetiology such as HPV is being increasingly implicated as is EBV in tonsillar tumours.
Premalignant lesions
Leukoplakia (white patch) is reported to undergo dysplastic change in 15% of cases and malignant change in 5% (some authorities believe that it is a benign lesion). Differential diagnosis includes candida and lichen planus (these can be scraped off; leukoplakia cannot). Erythroplakia (red patch) converts to SCC in 55% of cases. Differential diagnosis includes infection and iron deficiency anaemia. Diagnosis is by biopsy. Treatment is by excision, carbon dioxide laser ablation, or retinoids. Regular follow-up and cessation of risk factors is recommended.
Clinical features
Symptoms include pain, discharge, haemorrhage, swelling or mass, speech and swallowing difficulties, and bad breath. Site-specific symptoms include referred pain such as otalgia, trismus, hoarseness of voice, or stridor. Signs include a visible ulcer or palpable mass and palpable lymphadenopathy.
Diagnosis
History and examination, scrapings, incisional biopsy, or excisional biopsy if small. FNA of any palpable node. In patients who present with palpable lymphadenopathy and no obvious primary, blind biopsies of common occult tumour sites such as tongue base and tonsillar fossa at time of panendoscopy is indicated.
Investigations
Baseline blood investigations to look for malnutrition, anaemia, and liver metastases; FBC, U&E, LFT, thyroid function tests; clotting, cross-matching (pre-operative 4–6 U); CXR, OPG (if tumour may be invading mandible), CT/MRI (to detect the extent and infiltration of the tumour and any nodes >1.5 cm or spherical with central necrosis) including chest for staging. Comprehensive examination under anaesthetic should include palpation and panendoscopy (synchronous tumour is picked up in 1–6%).
TNM definitions for oral cavity and oropharynx
• TX: cannot assess primary tumour.
• T0: no evidence of primary tumour.
• Tis: carcinoma in situ.
• T1: tumour ≤2 cm.
• T2: tumour 2–4 cm.
• T3: tumour >4 cm.
• T4: tumour invades adjacent structures.
• T4 oral cavity invades (a) extrinsic muscles of the tongue, through cortical bone and into skin and maxillary sinus, and (b) pterygoid plates, masticator space, and skull base, and encases carotid artery.
• T4 oropharynx invades (a) larynx, extrinsic muscles of the tongue, medial pterygoid, hard palate, and mandible, and (b) lateral pterygoid, pterygoid plates, lateral nasopharynx, and skull base, or encases carotid artery.
• NX: nodes cannot be assessed.
• N0: no nodal metastases.
• N1: single ipsilateral node ≤3 cm.
• N2a: nodal metastases in ipsilateral nodes <6 cm.
• N2b: nodal metastases in multiple ipsilateral nodes <6 cm.
• N2c: nodal metastases in bilateral or contralateral nodes <6 cm.
• N3: nodal metastases >6 cm.
• MX: distant metastases cannot be assessed.
• M0: no distant metastases.
• M1: distant metastases.
TMN definitions for hypopharynx
• TX, T0, Tis: as oral cavity.
• T1: tumour ≤2 cm in one subsite of hypopharynx.
• T2: tumour size 2–4 cm; invades from one subsite but no fixation of the hemilarynx.
• T3: tumour >4 cm or with fixation of the hemilarynx.
• T4: invasion of tumour from hypopharynx into local structures.
Staging (AJCC 2002)
• Stage 0: Tis, N0, M0.
• Stage 1: T1, N0, M0.
• Stage 2: T2, N0, M0.
• Stage 3: T1–2, N1, M0 or T3, N0–1, M0.
• Stage 4: T1–3, N2–3, M0 or T4, N0–3, M0 or any T, any N, M1.
Management
This requires a multidisciplinary team including an oncological surgeon, reconstructive surgeon, specialist nurse, speech therapist, dietician, oral hygienist, dentist, prosthodontist, psychologist, social worker, administrative and audit support, and an ex-patient.
Supportive management
Assessment by the above team and ensure suitable pre- and post-operative support as appropriate. Pre-operative feeding via an NG tube, PEG tube, or jejunostomy. Blood transfusion or tracheostomy may be required. Effective pain control. Dental evaluation prior to radiotherapy. Help to stop smoking is important, as radiotherapy is less effective in patients who continue to smoke.
Treatment principles of primary tumours
T1 and mobile T2 tumours (stages 1 and 2) can be treated by either surgery or radiotherapy (external beam or brachytherapy). If, following surgery, these tumours are >5 mm deep or are incompletely excised, post-operative radiotherapy is indicated.
Larger or fixed tumours (stages 3 and 4) are generally treated with a combination of surgery, reconstruction, and post-operative radiotherapy. However, the treatment options must be adjusted on an individual patient basis, which is why the multidisciplinary approach is vital. It is important to take the general health and the preference of the patient, and the local expertise, into account. Radical radiotherapy and chemo-radiotherapy are alternatives in stage 3 and 4 disease at certain sites (e.g. tonsillar fossa and tongue base), where they are the preferred options in the infirm patient who will do poorly with the duration and stress of surgery required for major resection and reconstruction.
Excision margins
This should include the tumour and any in situ changes around it. Clearly defined tumour blocks are ideally excised with a 1 cm margin, and infiltrative or post-radiation recurrence with a 2 cm margin. Use frozen section analysis if any doubt exists.
Surgical approach
Accessible T1 and some T2 tumours can be excised via an intra-oral approach. Larger and more distant tumours will require a lip split and mandibular osteotomy.
Indications for primary radiotherapy
• T1 or T2 lesions.
• Indistinct margins.
• Synchronous primaries.
• Generalized field change.
• Patient choice.
• Infirm patient.
• No invasion of the mandible.
Treatment principles of neck nodes
In the N0 neck, node dissection is generally not performed for T1 tumours, but is performed for T3 and T4 tumours, including bilateral dissections where the tumour crosses the midline. The debate lies over T2 tumours. For sites where there is a high risk of occult metastases (e.g. the tongue and floor of mouth) or where the neck is opened for access (e.g. the oropharynx), a neck dissection should be performed (some authorities argue that this principle should also be applied to T1 tumours). Also consider performing a neck dissection when follow-up or monitoring of the neck may be difficult. Sentinel lymph node biopsy may have a future role in these patients.
Neck dissection should be performed on an N-positive neck. Surgeons can tailor the extent of the neck dissection depending on the N stage, the primary tumour site, and the proximity of the involved nodes to vital structures that should be preserved. For the N0 or N1 (<2 cm) neck, primary radiotherapy is an option with equivalent results.
Indications for post-operative radiotherapy
• Incomplete excision.
• Close excision (<5 mm).
• Extracapsular lymph node spread.
• N2 and N3 disease (some say any N-positive neck).
Poor prognostic factors
• High TNM stage.
• Thickness of tumour (>0.5 cm).
• Invasion of perineurium, lymph and blood vessels.
• Irregular pattern of invasion.
• Poorly differentiated tumour.
• Carotid adherence.
• Extracapsular spread from lymph nodes.
• Tumour recurrence.
Tumour recurrence
This is likely if excision is incomplete, margins are close (<0.5 cm), or margins contain in situ change. Note that 8.8% of ‘clear’ resections have positive margins.
Survival (5-year)
• Overall: <50%.
• Stage 1: 85%.
• Stage 2: 66%.
• Stage 3: 41%.
• Stage 4: 9%.
However, there are large variations depending on site.
Chemotherapy
Chemotherapy is generally used as part of a controlled trial or as part of the palliative regime in advanced or recurrent disease. Neoadjuvant chemotherapy (given prior to other modalities) has been used to shrink tumours to allow surgical treatment. Trials that demonstrate survival benefit are awaited.
Post-operative care
Intensive post-operative care as for free flaps. Test swallow 8–10 days post–operatively. Continuing supportive management as described above.
Follow-up
Close follow-up initially monthly after treatment to exclude recurrence and detect new primaries.
Recurrent disease
This requires careful pre-operative decision-making and counselling with the patient and the multidisciplinary team. If there is a curative intent this usually will require surgery and reconstruction in a previously operated or irradiated field which is associated with higher morbidity and mortality. If there is no curative possibility, palliative chemo- or radiotherapy (if not previously used), together with supportive and palliative care, will be needed.
Oral cavity
Treatment
T1 tumours can be treated with surgery or radiotherapy. Radiotherapy leaves better cosmesis and function, especially at the commissure, but surgery provides staging details, margin assessment, and is more rapid. Both achieve 90% local control. Excision margins for lesions smaller than 1 cm can be 0.5 cm, but anything larger should have a 1 cm margin. Mohs' surgery can be considered. A T2 tumour with N0 neck should be considered for prophylactic neck dissection. Field change of the vermilion is amenable to radiotherapy or vermilionectomy and mucosal advancement.
Reconstruction
Defects of <30% of the lip will close directly, with a W or barrel excision. Between 30% and 60% lip defect consider Abbé, Estlander, Johansen's step or Karapandzic flaps. Larger defects will require a Bernard–Webster, Gillies fan, or MacGregor flap. For total defects free tissue transfer is considered.
Buccal mucosa
Most tumours occur on or inferior to the plane of occlusion; 60% present having extended beyond the cheek mucosa. Advanced disease may necessitate parotidectomy and mandibular resection. An N0 neck has occult metastases in <10%. Depth of tumour is the most significant prognostic factor, as patients with tumours <6 mm have a >98% 5-year survival. Radiotherapy is the preferred option for small tumours around the commissure.
Gingiva and alveolar mucosa
This is often misdiagnosed, as it is similar to benign conditions such as gingivitis. It is most common in the molar area and invades the bone early. There is a high incidence of nodal metastases (T1, 25%). Small tumours are best treated with surgery with or without rim resection rather than radiotherapy. Deeper tumours require mandibulectomy. The N0 neck should be dissected.
Retromolar trigone
80% of these tumours occur in men. They present early and often with nodal disease (27–60%).
Floor of mouth
70% occur anteriorly near the lingual frenulum and the lymph drainage may be bilateral. T1 tumours can be treated by surgery or radiotherapy. T2 tumours encroaching on the mandible are better treated with surgery. Mandibular invasion occurs in 15–30%, and 30% of patients have positive nodes at presentation.
Mandible
Rim excision is performed in non-irradiated patients if the tumour is on the occlusal surface or has reached the alveolus but there are no clinical or radiological signs of involvement. Any doubt or definite involvement requires segmental resection. In irradiated mandibles, if the tumour is in close proximity to bone, segmental excision is carried out. If the mandible is edentulous and involved with tumour, segmental excision is the only option because of the poor bone stock.
Oropharynx
This site is associated with a high incidence of synchronous primaries. The tumour spreads into the nasopharynx and hypopharynx submucosally and often invades the prevertebral fascia.
Tongue base
The extent of tumour infiltration can be appreciated by palpation and ability to protrude the tongue (paralysis of CN XII). There are no pain fibres in the tongue base; hence these tumours are often painless until they have infiltrated further. When considering surgical treatment, manage- ment of the larynx is important. If the larynx is involved or the entire base of tongue and hypoglossal nerves need to be resected, laryngectomy should be considered. Nodal spread to ipsilateral nodes in 70% and bilateral in 30%.
Tonsils
There is a suggested link to EBV in primary tumours. 1% of tumours are secondary deposits. The internal carotid artery lies only 2.5 cm posterio-lateral to the tonsillar fossa and advanced tumours are often continuous with the neck nodes. Over 50% patients have positive nodes at presentation and dissection of the N0 neck is indicated.
Hypopharynx
Tumours in this area tend to spread submucosally, leaving an intact epithelium, and produce skip lesions. As a consequence the tumour is rarely localized to one subsite and tends to present with stage 3 or 4 disease in approximately 80% of patients. Up to 17% of patients may also have distant metastases.
Treatment
Laryngopharyngectomy, reconstruction, and post-operative radiation are the mainstay treatment for all stages of tumour. In the rare finding of a T1 tumour (1–2%), radiation alone may be used. Trials using chemo-radiotherapy without surgery have had some success but this should not be considered standard treatment.
Head and neck cancer reconstruction
Reconstructive principles
Allow remaining normal anatomy to return to place and function. Match type, volume, surface area, elasticity, and function of tissues removed.
Reconstructive aims
• Restore function of oral continence, speech, and swallowing.
• Cover vital structures and promote rapid healing to permit early adjunctive radiotherapy and prolong disease-free period.
• Restore external appearance.
• Resection and reconstruction is only the preferred alternative when it is done well with low morbidity.
Reconstructive options
Direct closure and secondary intention
Small tumours, T1, and some T2 can be excised with a laser or knife and left to mucosalize. This is best in areas where contraction of the wound will not distort function (e.g. tongue).
Skin grafts
These can be fenestrated and plicated in place for small intra-oral tumours. Their success rate is variable and often the wound mucosalizes when the graft disappears.
Local flaps
Intra-oral flaps have their place in selected cases but cause further distortion of local anatomy and the pedicle can limit the inset. They are also using oral mucosa which can be prone to further malignant change. The most commonly used is the buccinator flap, which requires an intact facial artery which may not be present after neck dissection. The nasolabial flap, based inferiorly and tunnelled through the cheek to lie intra-orally, is suitable for small inferior alveolar or floor of mouth tumours. Others that should be considered are submental and forehead flaps.
Reconstructive selection
Patient factors
The general health of the patient, their ability to withstand a major procedure, and the likelihood of post-operative problems must be considered. It may be necessary to compromise on the quality of the reconstruction if the risks are too great. For example, sometimes the pedicled flap may be indicated before the free flap.
Resection site
The size, site, three-dimensionality of the defect, and availability of a nerve for flap innervation may influence the reconstruction. Consider what is removed in terms of tissue bulk, content, and function (e.g. bone) to guide what may need to be replaced. Smaller defects that require pliable flaps in three dimensions, such as the oropharynx, will be better with a radial forearm flap, larger defects will be better with an anterior lateral thigh flap, and volume is provided by a VRAM. The vessels remaining in the neck, and hence the length of pedicle required, will also influence flap selection.
Donor site
Consider which donors are available and the morbidity associated with using them. The anterior lateral thigh defect, if directly closed, is a very low morbidity donor site. However, if it cannot be closed, it is a poor donor site.
The radial forearm flap and the anterior lateral thigh flaps are the workhorse flaps for mucosal replacement in the oral cavity and oropharynx. Taking the tongue as a whole organ, if up to 75% is removed the ideal construct is with an innervated radial forearm flap. If the total tongue is removed, more bulk is required to initiate swallowing and a VRAM or anterior lateral thigh flap is the best choice. In the hypopharynx, pharyngeal mucosa can be replaced by a radial forearm flap, anterior lateral thigh flap, or pectoralis major skin, tubed or as a patch as needed. Free jejunum may also be used, either opened for partial defects or as a tube. The choice depends on the factors outlined above and the level of expertise available. Occasional practitioners of jejunal flaps have higher complication rates and would be better served with tubing skin if they are more familiar with this technique.
Mandibular reconstruction
For small defects (<6 cm) a bone graft wrapped in well-vascularized tissue is sometimes used. However, failure rates of over 30% have been reported. Vascularized bone is the optimum reconstruction. The free fibula is the most often used because of the large amount of bone available, the ability to contour the bone, cortical thickness for implantation, and minimal donor site complication. Other options include the DCIA or the radial forearm flap with bone. Not performing a mandibular reconstruction in the elderly is an option for defects lateral to the parasymphyseal region when the TMJ has been removed. In these cases soft tissue reconstruction alone is used.
General consensus dictates that if a patient receives post-operative radiotherapy, osseo-integrated implants are not considered.
More than one flap may be required for large or composite defects. The fibula with skin can be used for bone and mucosal replacement. However, failure rates of up to 10% in the skin paddle are reported, and some surgeons advocate using two free flaps in this situation.
Peri-operative care
Prophylactic antibiotics, thromboprophylaxis, nutrition, oral hygiene, tracheostomy care, and flap observation will all be needed.
Complications
• Complications relating to excision:
• Haemorrhage, haematoma.
• Unintended damage to neurovascular structures.
• Incomplete excision.
• Recurrence.
• Complications relating to soft tissue reconstruction:
• Flap donor site complications.
• Flap necrosis.
• Incomplete healing with fistula formation.
• Infection.
• Insensate reconstruction.
• Chewing flap.
• Hair in mouth.
• Impaired swallowing of food.
• Drooling.
• Pooling of food.
• Impaired speech.
• Trismus.
• Psychological and psychosexual problems.
• Scarring and contour defects.
• Complications relating to bone reconstruction:
• Loosening, infection, or exposure of the osteotomy fixation.
• Bone necrosis.
• Bone resorption.
• Non-union or malunion.
• Complications relating to neck dissection:
• Lymph leak.
• Infection.
• Skin flap necrosis.
• Radiation complications especially:
• Xerostomia.
• Osteoradionecrosis.
Salivary gland tumours
Incidence
• 3% of head and neck tumours.
• 80% are in the parotid, and 80% of parotid masses are benign.
• 50% of submandibular, 50% of sublingual, and only 25% of accessory gland tumours are benign.
WHO classification
• Adenoma:
• Pleomorphic (60%).
• Adenolymphoma (Warthin's tumour, 8%).
• Oncocytoma.
• Carcinoma:
• Muco-epidermoid (9%).
• Malignant mixed tumour (arising in pleomorphic adenoma, 5%).
• Acinic cell.
• Adenocarcinoma.
• Adenoid cystic carcinoma (4%).
• Squamous carcinoma.
• Non-epithelial tumours:
• Soft tissue.
• Mesenchymal.
• Malignant lymphomas.
• Secondary tumours:
• Melanoma.
• SCC.
• Breast.
• Thyroid.
• Unclassified tumours.
• Tumour-like lesions.
• Sialadenosis.
• Oncocytosis.
• Cysts.
• Infection.
• Granulomatous disease.
Pleomorphic adenoma
Pleomorphic adenoma is a mixed tumour combining components of the duct epithelium, myoepithelium, and stroma. It is more common in women, and 2–10% undergo malignant change. It presents as a slow-growing lump that is firm and slightly irregular. Macroscopically it appears encapsulated, but often has invisible extensions (bosselations).
Warthin's tumour
Warthin's tumour is a lympho-epithelial tumour. It is five times more common in men, particularly smokers in their fifties. It is multicentric and bilateral (10%), and has a high recurrence rate.
Muco-epidermoid carcinoma
There are three grades. Well-differentiated tumours have a large number of mucous cells, limited local invasiveness, and rarely metastasize. Intermediate tumours behave in a similar fashion to a well-differentiated SCC. Poorly differentiated tumours are aggressive tumours that invade locally and metastasize regionally.
Adenoid cystic carcinoma
Adenoid cystic carcinoma exhibits unusual behaviour. It is prone to perineural and vascular invasion, skip lesions are common, and it excites very little host response. As a consequence it tends to be painless and can silently invade bone. There are three grades (Szanto):
• Grade 1 —cibrose (no solidity, good prognosis).
• Grade 2 —tubular (<30% solid).
• Grade 3 —solid (poor prognosis).
It can recur very late (after 25 years) and usually presents as lung metastases.
Clinical features of malignant salivary gland tumours
• Painful and hard lump arising in the body of the gland.
• Duct obstruction and infection.
• Bleeding from the duct.
• Invasion of local structures and fixation.
• In the parotid:
• Paralysis of CN VII.
• Ear problems.
• Trismus.
• Dysphagia with deep lobe involvement.
• Examination should be bilateral (exclude Sjögren's syndrome) and include intra-oral examination, bimanual palpation, and cranial nerve examination.
TNM classification
• TX, T0, Tis: as for oral cavity tumours.
• T1: tumour ≤2 cm with no clinical extraparenchymal extension.
• T2: tumour 2–4 cm without clinical extraparenchymal extension.
• T3: tumour >4 cm or having clinical extraparanchymal extension.
• T4: tumour into one of skin, mandible, ear canal, facial nerve, skull base, or around carotid.
Staging
• Stage 1: T1, N0, M0.
• Stage 2: T2, N0, M0.
• Stage 3: T3, N0, M0 or T1–3, N1, M0.
• Stage 4: T4, N0, M0 or T1–4 N 2–3 M0 or any T, any N, M1.
Investigations
• CT/MRI with gadolinium contrast of head neck and chest.
• Sialography.
• FNA or US-guided biopsy of tumour.
Treatment of parotid lumps
• Limited superficial parotidectomy, removing the tumour and a cuff of normal tissue, is performed for benign disease.
• Formal superficial parotidectomy is carried out for malignancy confined to this area.
• Total parotidectomy is performed if the tumour is large (T3) or in the deep lobe, preserving the facial nerve if it is not involved (this may involve splitting the tumour).
• Post-operative radiotherapy is indicated for malignant tumours and for benign tumours if excision is incomplete or the capsule is breached.
• A node-positive neck requires neck dissection.
• Some adjunctive chemotherapeutic regimens can be effective.
• If the pathology is uncertain, it is appropriate to perform a superficial parotidectomy with frozen section and proceed to total parotidectomy only if this is positive.
Superficial parotidectomy
Parotid anatomy
Bilateral gland found anterior and inferior to ear. Wraps around the posterior ramus of the mandible. Extends anteriorly over masseter. 75% of the gland is the superficial lobe lying anterior to the facial nerve. The posterior lobe has a retromandibular portion. The facial nerve enters the posterior aspect of the gland and separates the lobes. The connection between the lobes is called the isthmus.
The parotid duct (Stensen's duct) is 5–6 cm long and traverses the cheek in a line from the inter-tragal notch to the midpoint between the upper lip and the alar base, from the parotid to empty into the oral cavity through an orifice opposite the second upper molar. The parotid fascia attaches to the zygoma, masseter, and sternomastoid.
The parotid gland is supplied by parasympathetic branches that hitch a ride on the glossopharyngeal nerve after the otic ganglion from the inferior salivary nucleus.
Indications
Benign and low-grade malignant disease of the parotid gland superficial to the facial nerve. Removal of the lymph nodes within the parotid, usually as part of a neck dissection.
Aims
Removal of the superficial parotid gland with preservation of the facial and great auricular nerves.
Planning
Head up, shoulder pillow, head ring, LA with adrenaline, GA with no muscle relaxant, nerve stimulator, fine suction, and bipolar diathermy.
Incision
Modified Blair incision. Start at the upper border of the ear and continue down in the pre-auricular crease, curving in towards the pinna above the tragus and then out into the pre-auricular crease again. The incision loops under the ear lobe arches over the mastoid tip and turns anteriorly to run two fingerbreadths below the mandible, arching towards the hyoid bone.
Exposure
The skin incision is deepened through the SMAS–platysma layer and elevated in this plane off the parotid fascia. Posteriorly over the mastoid tip the skin flap is elevated off the SCM, taking care not to damage the great auricular nerve (as it courses obliquely across the upper third of the SCM) and the EJV.
Procedure
Start posteriorly by incising the investing fascia and elevating the posterior tip of the parotid gland off the mastoid tip and the anterior border of the SCM, taking great care not to cut the posterior facial vein (ligation causes congestion). Dissection should now proceed using mosquito forceps and bipolar cautery to free the gland from the ear canal and the zygomatic root. The next step is to identify the tragal pointer at the deep extent of the cartilaginous canal. The previous manoeuvres have ensured that this is done with greater access. The facial nerve lies 1 cm deep to this pointer. Suction, bipolar diathermy, and good retraction on the gland aid this search. The parotid is dissected off the bony canal and then in a plane parallel to the facial nerve. Connective tissue bands may look similar to the facial nerve; the use of a nerve stimulator facilitates identification of the nerve and is recommended.
Dissection progresses by placing the tips of the mosquito forceps in the perineural space lateral to the nerve. Tissue is cut down to the tips as they are lifted away from the nerve. The cut edges are clamped and diathermied. In a true superficial parotidectomy this is continued from the first branch off the main trunk to the termination of the gland. Sometimes, because of the placement of the tumour, it is necessary to perform retrograde dissection of the nerve. The options are to find the cervical branch as it runs with the retromandibular vein, the marginal branch superficial to the facial artery, or the buccal branch by cannulating Stensen's duct.
Complications
• Facial nerve division is the most significant complication. Primary repair or grafting where necessary should be carried out at the time.
• Frey's syndrome (gustatory sweating), which is caused when regenerating parasympathetic fibres from the facial nerve enter the skin. On response to stimuli the impulse errantly passes to these new connections, causing sweating. Skin flap re-elevation, with or without interposition of dermofat grafts or alloderm between nerve and skin at closure, has been recommended to treat this condition.
Neck dissection
Radical neck dissection (ND) is an operative procedure for the removal of the lymphatic field of the neck from the mandible above to the clavicle below, and from the midline to the anterior border of the trapezius. It is attributed to Crile (1906), who is said to have performed it in 45 minutes!
Anatomy
• The submandibular triangle is bounded by the anterior and posterior bellies of the diagastric muscle and the inferior border of the mandible.
• The submental triangle is bounded by the bilateral anterior bellies of digastric and the mandible.
• The upper jugular nodes are in the area from the skull base to the level of the hyoid. The anterior border is the sternohyoid and the posterior is the posterior border of the SCM (as for levels 3 and 4).
• Middle jugular nodes lie between the hyoid and the omohyoid muscle or cricothyroid membrane.
• Lower jugular nodes lie from the lower border of omohyoid to the clavicle.
• The posterior triangle is formed by the clavicle below and the posterior border of SCM and anterior border of trapezius muscle.
• Subclavicular and mediastinal nodes may also be involved and can be resected in a extended neck dissection.
Memorial Sloane–Kettering Cancer Center Classification
The cervical lymph nodes are described in terms of seven levels:
I Submental and submandibular triangles.
II Nodes around upper third of IJV and medial to SCM; above the level of the hyoid bone.
III Nodes around middle third of IJV and medial to SCM; above the level where the omohyoid crosses the IJV.
IV Lower jugular, scalene, and supraclavicular nodes deep to the lower third of SCM.
V Posterior triangle nodes.
VI Anterior.
VII Superior mediastinum.
The classification takes into account primarily the lymph node levels cleared, and secondarily the anatomical structures preserved. There are essentially three anatomical types of ND.
Extended
• Any of the other types are extended to include either a lymph node group not usually removed (such as paratracheal) or structures not routinely removed ( such as carotid artery).
• Extended radical ND includes levels 1–5 plus levels 6 and 7, and parotidectomy.
Comprehensive
• Radical ND includes clearance of levels 1–5 plus accessory nerve, SCM, and IJV.
• Three types of modified radical ND or functional ND:
• Type 1 preserves the accessory nerve.
• Type 2 preserves the accessory nerve and the SCM.
• Type 3 preserves the accessory nerve the SCM and the IJV (sometimes the term functional ND is reserved for this type).
Indications
• Neck lymph node metastases.
• Prophylactic neck dissection when size or site of tumour predicts likely lymph node spread.
Contraindications
Planning
Head up and tilted away from the operative side, with a sandbag under the shoulders. The upper chest, neck, and hemi-face should be prepared and draped.
Incision
There are many to choose from. The tri-radiate is the most commonly used. The upper incision lies in a cervical skin crease three fingerbreadths below the mandible, running from the mastoid to below the chin. The vertical limb lies at the junction of the posterior third and anterior two-thirds, to afford some protection to the great vessels in the event of a wound breakdown.
Exposure
The incisions are deepened through the platysma and flaps are raised in the subplatysmal plane. Caution should be exercised posteriorly where the SCM is close to the skin, and the flaps should be raised subcutaneously and superiorly where the marginal mandibular branch lies in the subplatysmal plane.
Procedure
The lymphatic contents are excised en bloc, commencing at the anterior border of the trapezius muscle. Incise down to the deep cervical fascia and peel the contents off this fascia as you move anteriorly. The omohyoid muscle is divided and taken with the specimen. Contents of the posterior triangle include the accessory and lesser occipital nerves and the transverse cervical vessels. The nerves from the cervical plexus are divided and direct you to the phrenic nerve lying on the scalenius anterior muscle. Take care not to go under the clavicle. Inferiorly the tissue is clipped and tied, including the external jugular vein. The SCM is divided and the IJV is tied, being cautious of the thoracic duct (on the left). The specimen is dissected superiorly off the vagus nerve and carotid artery. At the mastoid the SCM is divided and the top of the IJV is tied. Moving anteriorly, the submandibular fascia is incised and the facial vessels are tied, creating a superior flap which protects the marginal mandibular nerve. In the anterior corner of the dissection the lingual and hypoglossal nerves are located and Wharton's duct is tied. The gland is dissected of the mylohyoid muscle and the specimen cleared off the strap muscles to finish the dissection. The wound is washed out with sterile water.
Complications
Intra-operative
• Nerve injury.
• Carotid problems (bradycardia and emboli).
• IJV bleeding or air emboli.
• Lung problems (pneumothorax).
• Chyle leak.
Intermediate
• Infection.
• Deep vein thrombosis
• Pulmonary embolism.
• Pneumonia.
• Continuing wound problems (5–10%).
Late
• Seroma.
• Homer's syndrome.
• Poor cosmetic appearance.
• Shoulder pain syndrome.
• Accessory nerve damage.
• Neuroma.
• Recurrent tumour.
• Scar contracture.
• Fistula.
• Facial oedema.
• Cerebral oedema.
Carotid artery protection is essential in any patient whose skin wound is liable to break down (irradiated, poorly nourished, diabetic). A levator scapulae flap, dermal graft, or free flap may be used.