Tumours
of the oropharynx
Benign
Benign tumours of the oropharynx are rare, papillomas being the most
common. These are usually incidental findings and are rarely of any importance.
Malignant
The most important epithelial tumour is squamous cell carcinoma, which
constitutes roughly 90 per cent of all epithelial tumours in the upper
aerodigestive tract (Figs 43.30 and 43.31). In the oropharynx the proportion is
less (70 per cent) because of the higher incidence of lymphoma (25 per
cent) and salivary gland tumours (5 per cent).
Aetiology
Squamous carcinomas of the oropharynx have strong associations with
cigarette smoking and the consumption of alcohol, and these two
factors cause varying incidence throughout the world. In countries where
the consumption of tobacco and alcohol is associated with poor oral hygiene
these malignancies assume major importance. Due to the rich lymphatic drainage
of the oropharynx, cervical node metastatases are common. They may be the only
presenting feature with an apparent occult primary often being unsuspected and
missed in the tonsil or tongue base.
The majority of lymph node metastases from
oropharyngeal squamous carcinomas is to the jugulodigastric node. This is the
commonest site for the so-called ‘branchial cyst carcinoma’, but several
studies in recent times have shown that this is probably an extremely rare
pathology and that usually the diagnosis represents cystic degeneration in a
jugulodigastric node from a small undetected primary squamous carcinoma in the
tonsil or tongue base. Squamous cell carcinomas are most common in the sixth and
seventh decades and more frequent in men.
Treatment
Treatment patterns vary with facilities, hut early tumours may be cured
by radiotherapy, laser excision or more conventional excision. Recurrent
disease following radiotherapy is managed surgically, and repair of the
oropharynx may require regionally based myocutaneous flaps or free flaps with
microvascular anastomosis. Neck dissection is required in a large proportion of
cases of advanced disease. Postoperative dysphagia with aspiration, as a
result of interference in the complex neuromuscular control of the second phase
of swallowing, is a particular problem in these patients. More advanced tumours
may also require additional resection of the mandible or an associated total
laryngectomy, so this type of surgery is best carried out in a centre
undertaking this work on a regular basis.
Lymphoma
of the head and neck
Lymphomas of the head and neck may arise in nodal or extranodal sires,
and both Hodgkin’s disease and nonHodgkin’s lymphoma commonly present as
lymph node enlargement in the neck. Hodgkin’s disease is rare in the
oropharynx, but nonHodgkin’s lymphoma accounts for 15—20 per cent of tumours
at this site in some countries. Most are of the B-cell type and have features in
common with other tumours of MALT sires. Many of the lymphomas of the oropharynx
have no demonstrable deposit elsewhere in the body when a full lymphoma
investigation is carried out. On occasions, however, they may be secondary or
coincident with deposits at other sires in the neck, the gastrointestinal tract,
lung and the testes. Further evaluation with CT scanning of the thorax and
abdomen, and bone marrow evaluation are essential. Radiotherapy is undoubtedly
the treatment of choice for localised nonHodgkin’s lymphoma and may give
control rates as high as 75 per cent at 5 years. For disseminated
nonHodgkin’s lymphoma the treatment of choice is systemic chemotherapy.
Combination chemotherapy is used in patients with an unfavourable histological
type.